Staff Ride Handbook for 

the Attack on Pearl Harbor,

7 December 1941:

A Study of Defending America

LTC Jeffrey J. Gudmens

and the Staff Ride Team

Combat Studies Institute

Combat Studies Institute Press

Fort Leavenworth, Kansas 66027
Cover photos: The photo of the attack on Pearl Harbor on 7 December 1941 is 

from the Naval Historical Center. The photo of the 11 September 2001 attack on 

the World Trade Center is from the US Air Force Counterproliferation Center.
Staff Ride Handbook for 

the Attack on Pearl Harbor, 

7 December 1941:

A Study of Defending America

LTC Jeffrey J. Gudmens

and the Staff Ride Team

Combat Studies Institute

Combat Studies Institute Press

Fort Leavenworth, Kansas 66027
Library of Congress Cataloging-in-Publication Data

Gudmens, Jeffrey J., 1960-

Staff ride handbook for the attack on Pearl Harbor, 7 December 1941 : 

a study of defending America / Jeffrey J. Gudmens and the Staff Ride 

Team, Combat Studies Institute.

p. cm.

 Includes bibliographical references.

 1. Pearl Harbor (Hawaii), Attack on, 1941. 2. United States—Armed 

Forces—Organization. 3. Japan—Armed Forces—Organization. 4. Pearl 

Harbor (Hawaii)—Tours. I. U.S. Army Combined Arms Center. Combat 

Studies Institute. Staff Ride Team. II. Title.

 D767.92.G84 2005

 940.54’266931—dc22

2005025669
i

Foreword

The Pearl Harbor Staff Ride Handbook is the ninth study in the Combat Studies Institute’s (CSI’s) Staff Ride Handbook series. LTC Jeffrey 

Gudmens’ handbook on Pearl Harbor allows individuals and organizations 

to study this battle not only in the context of the Japanese attack but, more 

importantly, in the context of issues that are relevant to the current global 

war on terror. In addition to analyzing the actual attack, Gudmens also 

enables users of this work to examine the problems associated with conducting joint planning and operations between the US Army, the Army Air 

Forces, and the US Navy. He also provides insights into the problems of a 

Homeland Security environment in which intelligence operatives from a 

foreign nation (and potentially even recent immigrants from that foreign 

nation who are now US citizens) can operate with little hindrance in a free 

and open democratic society. Additionally, this study provides an opportunity to look at how military commanders and planners prepared for their 

wartime mission with inadequate resources and equipment. Each of these 

issues, and others analyzed herein, is as relevant to us today as it was almost 65 years ago. Modern military professionals for whom this handbook 

was written will find a great deal to ponder and analyze when studying the 

events leading up to, and including, the attack on Pearl Harbor. They are 

lessons that we cannot afford to forget. CSI—The Past is Prologue!

Timothy R. Reese

Colonel, Armor

Director, Combat Studies Institute

iii

Contents

Page

Foreword....................................................................................................i

Figures.......................................................................................................v

Introduction...............................................................................................1

I. The Militaries.....................................................................................5

US Organization .................................................................................5

Japanese Organization......................................................................14

 Ships.................................................................................................18

 Aircraft Carriers.........................................................................18

 Japanese Aircraft Carriers ...................................................19

 American Aircraft Carriers..................................................22

 Battleships..................................................................................23

 Japanese Battleships............................................................24

 American Battleships...........................................................25

 Cruisers................................................................................28

 Destroyers............................................................................29

 Submarines..........................................................................30

Aircraft..............................................................................................32

 Fighters ......................................................................................32

 Japanese Fighter..................................................................32

 American Fighters...............................................................33

 Bombers.....................................................................................34

 Japanese Bombers...............................................................35

 American Bombers..............................................................36

Strategy...... ......................................................................................38

Operational .......................................................................................42

 Tactics .............................................................................................43

Logistics ...........................................................................................45

II. Pearl Harbor Campaign Overview ...................................................47

III. Suggested Route and Vignettes........................................................63

Introduction ......................................................................................63

Stand 1. Japanese Espionage ...........................................................67

Stand 2. Homeland Defense ............................................................71

Stand 3. American Intelligence .......................................................75

Stand 4. American Preparations ......................................................80
iv 

Page

Stand 5. “Joint” Defenses ...........................................................88

Stand 6. Preparednes and Early Warning....................................94

Stand 7. Japanese Air Superiority...............................................99

Stand 8. Japanese Torpedo Attack ............................................104

Stand 9. Japanese High-Level Attack .......................................108

Stand 10. Japanese Second Wave ............................................... 113

Stand 11. Aftermath.................................................................... 119

IV. Integration Phase for the Attack on Pearl Harbor........................... 123

V. Support for a Staff Ride to Pearl Harbor........................................ 129

Appendix A. Order of Battle, Japanese Forces................................... 131

Appendix B. Order of Battle, US Forces............................................ 137

Appendix C. Biographical Sketches ................................................... 143

Appendix D. Medal of Honor Conferrals for the Attack on

Pearl Harbor...................................................................153

Bibliography .........................................................................................159

About the Author...................................................................................163
v

Figures

Page

1. US War Department Organization......................................................5

2. Hawaiian Department Organization...................................................7

3. US Navy Department Organization ...................................................8

4. US Chief of Naval Operations Organization......................................9

5. Pacific Fleet Organization ................................................................10

6. Task Force 1 Organization................................................................ 11

7. Task Force 2 Organization................................................................12

8. Task Force 3 Organization................................................................13

9. Japanese Government Organization.................................................14

10. Combined Fleet Organization, 1941 ................................................16

11. Combined Fleet Organization, December 1941 ...............................17

12. HMS Argus.......................................................................................18

13. Akagi.................................................................................................19

14. Kaga .................................................................................................20

15. Soryu.................................................................................................20

16. Hiryu.................................................................................................20

17. Shokaku ............................................................................................21

18. Zuikaku .............................................................................................21

19. USS Lexington, CV-2 .......................................................................22

20. USS Saratoga, CV-3 ........................................................................22

21. USS Enterprise, CV-6 ......................................................................23

22. Hiei ...................................................................................................24

23. Kirishima..........................................................................................24

24. USS Nevada, BB-36, Nevada Class.................................................25

25. USS Oklahoma, BB-37, Nevada Class ............................................25

26. USS Pennsylvania, BB-38, Pennsylvania Class ..............................26

27. USS Arizona, BB-39, Pennsylvania Class .......................................26

28. USS Tennessee, BB-43, Tennessee Class.........................................26

29. USS California, BB-44, Tennessee Class ........................................27
vi 

Page

30. USS Maryland, BB-46, Colorado Class...........................................27

31. USS West Virginia, BB-48, Colorado Class.....................................27

32. Japan’s Furutaka ..............................................................................28

33. USS New Orleans, CA-32, New Orleans Class...............................28

34. Japan’s Amagiri ................................................................................29

35. USS Helm, DD-388, Bagby Class....................................................29

36. Japan’s I-68.......................................................................................30

37. Japan’s HA-19...................................................................................31

38. USS Tautog, SS-199, Tambor Class.................................................31

39. A6M2 Zero Fighter ..........................................................................32

40. P-40 Warhawk ..................................................................................33

41. P-36 Hawk........................................................................................33

42. F4F3 Wildcat ....................................................................................34

43. B5N2 Kate Torpedo/High-Level Bomber ........................................35

44. D3A Val Dive Bomber .....................................................................35

45. B-17B Flying Fortress......................................................................36

46. B-18 Bolo .........................................................................................36

47. PBY-5 Catalina .................................................................................37

48. SBD-2 Dauntless Dive Bomber .......................................................37

49. TBD-1 Devastator Torpedo/High-Level Bomber.............................38

50. Rainbow War Plans ..........................................................................40

51. “Crossing the T”...............................................................................43

52. Main Force .......................................................................................44

53. Southern Operation, Dec-Jan 41 ......................................................56

54. Fuchida Chart ...................................................................................61

55. Hawaiian Department Critical Sites.................................................72

56. Battery Hawkins, Early 1920s..........................................................81

57. Organization of the Hawaiian Coast Artillery Command ................83

58. Organization of the Hawaiian Department Mobile Forces...............83

59. Organization of the Hawaiian Air Force ..........................................84
vii

Page

60. Battery Hasbrouck, Early 1920s.......................................................88

61. Interceptor Command.......................................................................91

62. USS Ward .........................................................................................96

63. Radar Track From Opana Radar Site ...............................................97

64. Japanese Planes Prepare for Takeoff, 7 December 1941................100

65. First-Wave Plan ..............................................................................101

66. Wheeler AAF Under Attack, 7 December......................................102

67. Pearl Harbor at 0757, 7 December 1941 ........................................104

68. Torpedo Attack on Pearl Harbor.....................................................105

69. Battleship Row as Seen From a Japanese High-Level Bomber.....109

70. The USS Arizona Exploding After Being Hit by a

High-Level Bomb...........................................................................109

71. Battleship Row After the First Wave.............................................. 110

72. Lieutenant Commander Samuel G. Fuqua ..................................... 111

73. Second-Wave Plan.......................................................................... 114

74. The USS Cassin Resting on the USS Downes After the Attack .... 115

75. The USS Shaw Explodes on 7 December ...................................... 115

76. The USS Nevada on Fire and Trying to Head to Sea..................... 116

77. Twenty-One Winches Right the USS Oklahoma ...........................121

Stand Maps

Map to Stands 1-3 ...................................................................................64

Map to Stands 4-7 ...................................................................................65

Map to Stands 8-10 .................................................................................66
1

Introduction

Surprise, when it happens to a government, is likely to 

be a complicated, diffuse, bureaucratic thing. It includes 

neglect of responsibility, but also responsibility so poorly 

defined or so ambiguously delegated that action gets lost. 

It includes gaps in intelligence, but also intelligence that, 

like a string of pearls too precious to wear, is too sensitive 

to give to those who need it. It includes the alarm that fails 

to work, but also the alarm that has gone off so often it 

has been disconnected. It includes the unalert watchman, 

but also the one who knows he’ll be chewed out by his 

superior if he gets higher authority out of bed. It includes 

the contingencies that occur to no one, but also those that 

everyone assumes somebody else is taking care of. It 

includes straightforward procrastination, but also decisions protracted by internal disagreement. It includes, in 

addition, the inability of individual human beings to rise 

to the occasion until they are sure it is the occasion which 

is usually too late. Finally . . . surprise may include some 

measure of genuine novelty introduced by the enemy, and 

possibly some sheer bad luck.*

In his farsighted foreword to Roberta Wohlstetter’s excellent book 

about our failures before Pearl Harbor, Thomas C. Schelling described 

how and why the Japanese were able to successfully attack the US Pacific Fleet at Pearl Harbor in 1941. Prophetically, his words ring true in 

describing the successful al-Qaeda attack against the United States on 11 

September 2001.

On 7 December 1941 the United States suffered a devastating surprise 

attack that thrust it into a worldwide war. Our enemy had extensively 

planned the attack, conducted detailed reconnaissance of its target to 

determine how to achieve the most destruction, and had innovatively 

planned the operation to overcome all obstacles. Two services that needed 

to work together were never ordered to do so, losing synergy that was 

sorely needed. The United States had indications that an attack was possible but had no single agency to gather all of the available information 

for an analysis that would suggest an attack. When the attack started, there 

were indications that something large was happening, but the word was 

never spread, and our enemy’s attack was devastating.

Sixty years later the United States was again thrust it into a worldwide 
2 

war. On 11 September 2001 enemies of our nation conducted an overwhelming surprise attack against our homeland. Our enemy had again 

meticulously planned the operation and conducted extensive reconnaissance of its targets before its destructive attacks. Many agencies in our 

government had indications of an attack, but again, there was no single 

agency that analyzed all available intelligence to provide us a warning. As 

word of the attack spread, people refused to accept that the impossible was 

happening, and again our enemy delivered an overwhelming attack.

As our nation prosecutes the global war on terrorism, it is imperative 

that we in the profession of arms study those events in which our homeland 

has been successfully and directly attacked in the past. While attacking our 

enemies around the world, we must first ensure that our homeland remains 

completely protected and safe. Not only should we study the tactics, techniques, and procedures of recent operations, but we also need to study history—events where we analyze the actions of both attacked and defender 

so we are better prepared to handle similar situations that may arise in the 

future. We should study what mistakes we made and what things we did 

well as well as the enemy’s successes and failures. We must do all of this 

to increase our ability to prevent another attack on the United States.

The United States is a nation in which it is easy to move about and see, 

even in a time of war, and our homeland is now a part of the battlespace, 

a target for our enemies. How do we prevent an enemy from observing 

a target when it is not overtly breaking the law? Our many intelligence 

agencies provide outstanding intelligence, but how do we gather all of 

the information to synergistically determine our enemies’ intentions and 

get this information to the commanders who need it? Our job is to keep 

America safe, and even when we are in the midst of fighting a war, it is 

critical that we take the time to study the past so we do not make the same 

mistakes in the future.

A staff ride has three distinct phases—a preliminary study, a field 

study, and integration (see The Staff Ride by Dr. William G. Robertson, 

published by the Center of Military History, for information on planning 

and conducting staff rides). The preliminary study phase prepares students 

to travel to the field and can be conducted through individual study, instructor-led lectures, discussion, or a combination of these. The field study 

phase allows students to better understand historical events by studying 

them from actual locations. Finally, the integration phase allows the students to understand what happened, why it happened, and most important, 

what can be learned by studying the battle.
3

The Staff Ride Handbook for the Attack on Pearl Harbor, 7 December 

1941 provides a systematic approach to analyzing how Japan planned for 

the attack, the failures the United States made in preventing it, and the 

attack’s disastrous results. Throughout the book, pragmatic comparisons 

of 7 December 1941 and 11 September 2001 are presented for analysis and 

discussion. Part I describes the organization of the Japanese and American 

forces, detailing their respective ships, aircraft, strategy, tactics, and logistics. Part II consists of a campaign overview that encompasses the road to 

war, planning, and intelligence, allowing students to understand how the 

forces met on the battlefield.

Part III consists of a suggested route to use in conducting a staff ride 

of the attack on Pearl Harbor. For each stop, or “stand,” there is a set of 

travel directions, an orientation, a description of the action or event that 

occurred there, and most important, a list of discussion points that a staff 

ride leader can explore at each stand. Part IV provides information on conducting the integration phase of this staff ride and suggests areas to discuss 

during the integration phase. Part V provides administrative information 

on conducting a staff ride at Pearl Harbor, including sources of assistance 

and logistics considerations. Appendix A provides the Japanese order of 

battle at Pearl Harbor while Appendix B provides the order of battle of 

American forces in Hawaii during the battle. Appendix C gives brief biographical information on key participants. Appendix D is a list of Medal of 

Honor recipients from the Pearl Harbor attack. An annotated bibliography 

provides sources for preliminary study.

All dates used in this book are Hawaiian time (Japan is one day ahead 

of Hawaii). The attack on Pearl Harbor occurred on 7 December, which 

was 8 December in Japan.

*Roberta Wohlstetter, Pearl Harbor: Warning and Decision (Stanford, CA: 

Stanford University Press, 1962), viii.

5

I. The Militaries

US Organization

In 1941 Franklin D. Roosevelt was the President of the United States 

and, as such, was Commander in Chief of the Army and Navy. He was assisted by the Secretary of War who oversaw the Army, including the Army 

Air Forces, and the Secretary of the Navy who oversaw the Navy and the 

Marine Corps.

The Secretary of War in 1941 was Henry L. Stimson, who was 74 

years old (see figure 1). Stimson had served as the Secretary of War, 

1911-1913; Secretary of State, 1929-1933; and had begun his second term 

as Secretary of War in July 1940. The Army Chief of Staff was General 

George C. Marshall, 60 years old at the time of the attack, who had been 

Chief of Staff since 1939. Under Marshall were three deputy chiefs of staff 

and his staff (the G1, G2, G3, and G4 and the War Plans Division).

US War Department Organization

7 December 1941

Secretary of War

Henry L. Stimson

Chief of Staff

GEN George C.

Marshall

DCS/Gen Admin

and Ground Forces

MG W. Bryden

DCS/Armored Forces

and Supply

MG R.C. Moore

DCS/Air

MG H.H. Arnold

Special Staff

Chiefs and

Administrative

Bureaus1

Corps

Areas

Field

Forces

Air

Forces3

Overseas

Establishments4

1. Areas including JAG, finance, chaplain, QM, surgeon general, etc.

2. Infantry, cavalry, field artillery, engineers, signal.

3. Air Force Combat Command and other (air service, ferrying, training, etc.) commands.

4. Hawaiian Department, US Army forces in the Far East, Atlantic bases, and Caribbean

Defense Command.

Chiefs of

Arms2

General Staff

G1, G2, G3,

G4, WPD

US War Department Organization

7 December 1941

Secretary of War

Henry L. Stimson

Secretary of War

Henry L. Stimson

Chief of Staff

GEN George C.

Marshall

DCS/Gen Admin

and Ground Forces

MG W. Bryden

DCS/Armored Forces

and Supply

MG R.C. Moore

DCS/Air

MG H.H. Arnold

Special Staff

Chiefs and

Administrative

Bureaus1

Corps

Areas

Field

Forces

Air

Forces3

Overseas

Establishments4

1. Areas including JAG, finance, chaplain, QM, surgeon general, etc.

2. Infantry, cavalry, field artillery, engineers, signal.

3. Air Force Combat Command and other (air service, ferrying, training, etc.) commands.

4. Hawaiian Department, US Army forces in the Far East, Atlantic bases, and Caribbean

Defense Command.

Chiefs of

Arms2

General Staff

G1, G2, G3,

G4, WPD

Figure 1.
6 

Under the General Staff were six different component groupings. The 

first group was the chiefs of the service and administrative bureaus (ordnance, quartermaster [QM], judge advocate general [JAG], finance, etc.) 

that kept the Army’s administration, supply, and services straight. Next 

were the chiefs of arms, the branches responsible for doctrine and training the soldiers assigned to the field forces. The continental United States 

(CONUS) was geographically divided into nine corps areas, the headquarters of which were responsible for training, administration of, and mobilizing Regular Army, Reserve, and National Guard units within their corps 

areas. The Chief of Staff was also the commander of the field forces, the 

“warfighters” of the Army. Field forces were broken down into a CONUS 

section and an overseas establishment. Air forces was the fifth component 

grouping, which was broken down into combat commands (the numbered 

air forces) and other commands (training, ferrying, etc.).

The last component, which was really a subcomponent of the field 

forces, was overseas establishments. It was broken down into four subcomponents: the Hawaiian Department, US forces in the Far East, Atlantic 

bases, and the Caribbean Defense Command. In December 1941 the Army 

had 1,600,000 men on active duty. The US Army’s Hawaiian Department 

(see figure 2) had 42,857 men in December 1941 and was commanded by 

Lieutenant General (LTG) Walter C. Short, who was 61. The Hawaiian 

Department’s mission was to defend the Pearl Harbor Naval Base against 

attack from the air, by expeditionary forces, enemy fleets, or sympathizers. To do this, Short had two understrength divisions, four antiaircraft 

(AA) regiments, four harbor defense regiments (two incomplete), a bombardment wing, a pursuit wing, aircraft warning units, and other support 

units.

The Hawaiian Department was plagued by shortages of vital equipment. The air defense regiments had 86 of 98 authorized 3-inch AA guns, 

20 of 120 37-millimeter (mm) guns, and 113 of 246 .50-caliber machine 

guns. The Hawaiian Army Air Force had only 12 of the modern B-17s, 33 

B-18s (obsolete), and 12 A-20s. For fighters, it had 99 modern P-40s and 

53 obsolete P-36s and P-26s. The Hawaiian Department was also short 

extended-range reconnaissance aircraft. The aircraft warning units had 

only received three of six authorized long-range fixed radar sets, but the 

National Park Service held up installation on property that it controlled, 

so on 7 December none were operational. The Hawaiian Department additionally had six mobile radar sets, but due to a lack of qualified crews, 

they were only operational a few hours each day.

The Secretary of the Navy in 1941 was Frank Knox, who was 67. At
7

the outbreak of the Spanish-American War, Knox enlisted and joined Theodore Roosevelt’s “Rough Riders.” Knox was impressed with Roosevelt 

and became one of his main advisers. Knox had been a newspaperman. 

Starting as a reporter, he worked his way up to general manager of all of 

William Randolph Hearst’s newspapers and finally to become the publisher of the Chicago Tribune. Despite being a Republican, Franklin Roosevelt 

98th Coast

Artillery Regt

(Semimobile AA)

Hawaiian Department Organization

7 December 1941

Commander

LTG Walter C.

Short

24th Division

BG D.S. Wilson

25th Division

MG M. Murray

Coast Artillery

Command

MG H.T. Burgen

Hawaiian Army

Air Force

MG F.L. Martin

18th

Bombardment

Wing

14th

Pursuit Wing

Hickam

Field

Wheeler

Field

Bellows

Field

19th Infantry

21st Infantry

299th Infantry

27th Infantry

35th Infantry

298th Infantry

15th Coast

Artillery Regt

(Harbor Def)

16th Coast

Artillery Regt

(Harbor Def)

41th Coast

Artillery Regt

(Railway)

55th Coast

Artillery Regt

(155)

64th Coast

Artillery Regt

(Semimobile AA)

97th Coast

Artillery Regt

(Semimobile AA)

251st Coast

Artillery Regt

(Mobile AA)

98th Coast

Artillery Regt

(Semimobile AA)

Hawaiian Department Organization

7 December 1941

Commander

LTG Walter C.

Short

24th Division

BG D.S. Wilson

25th Division

MG M. Murray

Coast Artillery

Command

MG H.T. Burgen

Hawaiian Army

Air Force

MG F.L. Martin

18th

Bombardment

Wing

14th

Pursuit Wing

Hickam

Field

Wheeler

Field

Bellows

Field

19th Infantry

21st Infantry

299th Infantry

27th Infantry

35th Infantry

298th Infantry

15th Coast

Artillery Regt

(Harbor Def)

16th Coast

Artillery Regt

(Harbor Def)

41th Coast

Artillery Regt

(Railway)

55th Coast

Artillery Regt

(155)

64th Coast

Artillery Regt

(Semimobile AA)

97th Coast

Artillery Regt

(Semimobile AA)

251st Coast

Artillery Regt

(Mobile AA)

Figure 2.
8 

appointed him Secretary of the Navy. Knox’s Chief of Naval Operations 

(CNO) was Admiral Harold R. Stark, who was 61 and had spent his career 

as a battleship and cruiser man.

The Navy Department’s organization (see figure 3) was similar to that 

of the War Department, but there were some differences. Like the War 

Department, there were many administrative and logistics bureaus (ordnance, supplies and accounts, and ships), but unlike the War Department, 

the Navy bureaus worked directly for the Secretary of the Navy. The CNO 

coordinated with these agencies, but he had no direct command authority. 

The US Marine Corps (USMC) also directly reported to the Secretary of 

the Navy.

US Navy Department Organization

7 December 1941

Secretary of the Navy

Henry L. Stimson

Chief of Naval Operations

ADM Harold R. Stark

Bureau

of Navigation

Ordnance

Aeronautics

Ships

Yards and Docks

Supplies and Accounts

Medicine and Surgery

Headquarters,

Marine Corps

Operating Forces,

Marine and Naval

Districts

US Navy Department Organization

7 December 1941

Secretary of the Navy

Henry L. Stimson

Chief of Naval Operations

ADM Harold R. Stark

Bureau

of Navigation

Ordnance

Aeronautics

Ships

Yards and Docks

Supplies and Accounts

Medicine and Surgery

Headquarters,

Marine Corps

Operating Forces,

Marine and Naval

Districts

Figure 3.
9

The CNO was the Navy’s warfighter (see figure 4) and was charged 

with “the operations of the fleet, and with preparation and readiness of 

plans for its use in war. . . .” The CNO’s main warfighting subordinates 

were the commanders of the Atlantic Fleet, Pacific Fleet, and Asiatic Fleet. 

The senior of these three fleet commanders was also designated as the 

Commander, US Fleet, whose mission was to command if two or more 

fleets were combined. The Naval Coastal Frontier Forces were responsible 

for defending ports and other coastal areas deemed important to the Navy.

The special task forces were groupings of ships task organized and assembled for particular missions, and once the mission was complete they were 

disbanded. Special duty ships were ships that performed specific missions, 

such as surveys, that the Navy only had a few of. The Navy Transportation 

Figure 4.

Transportation

Service

US Chief of Naval Operations Organization

7 December 1941

Chief of Naval Operations

ADM Harold R. Stark

Atlantic Fleet

ADM Ernest J.

King

Pacific Fleet

ADM Husband E.

Kimmel

Asiatic Fleet

ADM Thomas C.

Hart

Coastal

Frontier

Forces

Special

Task

Forces

Special

Duty

Ships

Naval

District

Craft

US

Fleet

(Kimmel)

Transportation

Service

US Chief of Naval Operations Organization

7 December 1941

Chief of Naval Operations

ADM Harold R. Stark

Atlantic Fleet

ADM Ernest J.

King

Pacific Fleet

ADM Husband E.

Kimmel

Asiatic Fleet

ADM Thomas C.

Hart

Coastal

Frontier

Forces

Special

Task

Forces

Special

Duty

Ships

Naval

District

Craft

US

Fleet

(Kimmel)
10 

Service was responsible for all logistics shipping while the naval district 

craft were specific craft assigned to support naval districts (floating dry 

docks, submarine chasers, etc.).

On 7 December 1941 the US Navy had 800 commissioned vessels 

(eight carriers, 17 battleships, 18 heavy cruisers, 19 light cruisers, 171 destroyers, 112 submarines, 87 patrol craft, 66 minecraft ships, 184 tenders, 

67 supply ships, 37 transports, and 14 special duty ships) and 284,000 men 

serving (plus 54,000 marines). The Commander in Chief, Pacific Fleet 

(CINCPAC) since February 1941 was Admiral Husband E. Kimmel, who 

was 59 years old. He had spent his career serving as a battleship man. 

Kimmel organized the Pacific Fleet into task forces for operations and 

training (see figure 5). Task Forces 1, 2, and 3 were the main warfighting 

Pacific Fleet Organization

7 December 1941

CINCPAC

ADM Husband E.

Kimmel

Task Force 1

VADM W.

Pye

Task Force 2

VADM W.

Halsey

Task Force 3

VADM W.

Brown

Task Force 4

RADM C.

Bloch

Task Force 7

RADM T.

Withers

Task Force 9

RADM P.

Bellinger

Task Force 15

RADM W.

Calhoun

14th Naval

District

Cdr, Submarines

Scouting Force

30 submarines

4 sub tenders

Cdr, Patrol

Wing 2

78 PBYs

9 Seaplane

tenders

Cdr, Base Force

4 cruisers

Cdr, Battle Force Cdr, Aircraft

Battle Force

Cdr, Scouting Force

Pacific Fleet Organization

7 December 1941

CINCPAC

ADM Husband E.

Kimmel

Task Force 1

VADM W.

Pye

Task Force 2

VADM W.

Halsey

Task Force 3

VADM W.

Brown

Task Force 4

RADM C.

Bloch

Task Force 7

RADM T.

Withers

Task Force 9

RADM P.

Bellinger

Task Force 15

RADM W.

Calhoun

14th Naval

District

Cdr, Submarines

Scouting Force

30 submarines

4 sub tenders

Cdr, Patrol

Wing 2

78 PBYs

9 Seaplane

tenders

Cdr, Base Force

4 cruisers

Cdr, Battle Force Cdr, Aircraft

Battle Force

Cdr, Scouting Force

Figure 5.
11

task forces. Task Force 4 was the naval district commanded by Rear Admiral Claude C. Bloch. Its mission was to organize, train, and develop the 

bases—Pearl Harbor, Midway, and Wake—and provide service to fleet 

units engaged in operations.

Task Force 7, under the command of Rear Admiral Thomas Withers, 

was a submarine force whose mission was to provide submarine operations for offensive operations, either independently or in conjunction with 

other fleet units or bases. Rear Admiral Patrick Bellinger commanded 

Task Force 9 whose mission was to provide long-range air scouting and 

air striking forces for the fleet. Task Force 15 was commanded by Rear 

Admiral William Calhoun and was responsible for protecting trans-Pacific 

shipping. In December 1941 the Pacific Fleet had three aircraft carriers, 

nine battleships, 22 cruisers, and 53 destroyers.

Vice Admiral William Pye (see figure 6) commanded Task Force 1, 

Figure 6.

Task Force 1 Organization

7 December 1941

(at Pearl Harbor)

Cdr, Battle Force

VADM William

Pye1

Battleship

Division

Two

USS Tennessee

USS California

USS Pennsylvania2

Battleship

Division

Four

USS West Virginia

USS Colorado3

USS Maryland

Cruiser

Division

Nine

USS Honolulu

USS Phoenix

USS Boise4

USS Helena

USS ST. Louis

USS Richmond4

Destroyer

Squadron

One

9 destroyers

Submarine

Division

Twenty-Two

6 submarines

Destroyer

Squadron

Three

9 destroyers

Submarine

Division

Sixty-One

6 submarines

Minecraft

Task Force

One

5 minelayers

Notes

1. USS Saratoga was part of this task force but was in San Diego on 7 Dec 41

after undergoing overhaul.

2. Flagship of the task force.

3. Undergoing overhaul at Puget Sound Naval Yard on 7 Dec 41.

4. On detached duty.

Task Force 1 Organization

7 December 1941

(at Pearl Harbor)

Cdr, Battle Force

VADM William

Pye1

Battleship

Division

Two

USS Tennessee

USS California

USS Pennsylvania2

Battleship

Division

Four

USS West Virginia

USS Colorado3

USS Maryland

Cruiser

Division

Nine

USS Honolulu

USS Phoenix

USS Boise4

USS Helena

USS ST. Louis

USS Richmond4

Destroyer

Squadron

One

9 destroyers

Submarine

Division

Twenty-Two

6 submarines

Destroyer

Squadron

Three

9 destroyers

Submarine

Division

Sixty-One

6 submarines

Minecraft

Task Force

One

5 minelayers

Notes

1. USS Saratoga was part of this task force but was in San Diego on 7 Dec 41

after undergoing overhaul.

2. Flagship of the task force.

3. Undergoing overhaul at Puget Sound Naval Yard on 7 Dec 41.

4. On detached duty.
12 

which had an aircraft carrier, six battleships, and six cruisers. Task Force 

1’s missions were to cover the operations of any other task force and to 

engage an enemy in fleet action. In December 1941 Task Force 1’s aircraft 

carrier and one of its battleships were on the west coast of the United 

States undergoing overhaul.

Vice Admiral William Halsey commanded Task Force 2, which had an 

aircraft carrier, three battleships, and four cruisers (see figure 7). Its mission was to conduct raids on enemy objectives, particularly on land. On 28 

November 1941 Kimmel organized Task Force 8—Task Force 2’s carrier, 

cruisers, and half of its destroyers—and sent it to Wake Island to deliver 

Figure 7.

Task Force 2 Organization

7 December 1941

(215 miles west of Pearl Harbor)

Cdr, Aircraft,

Battle Force

VADM William

Halsey

Battleship

Division

One1

USS Arizona

USS Nevada

USS Oklahoma

Carrier

Division

Two

USS Enterprise2

Cruiser

Division

Five

USS Northampton

USS Salt Lake City

USS Pensacola4

USS Chester

Destroyer

Squadron

Four1

9 destroyers

Submarine

Division

Forty-Two3, 4

4 submarines

Destroyer

Squadron

Six

9 destroyers

Submarine

Division

Sixty-Two3, 4

6 submarines

Minecraft

Task Force

Two1

4 minelayers

Notes

1. Left at Pearl Harbor.

2. Flagship of the task force.

3. Elements left at Pearl Harbor.

4. On detached duty.

Task Force 2 Organization

7 December 1941

(215 miles west of Pearl Harbor)

Cdr, Aircraft,

Battle Force

VADM William

Halsey

Battleship

Division

One1

USS Arizona

USS Nevada

USS Oklahoma

Carrier

Division

Two

USS Enterprise2

Cruiser

Division

Five

USS Northampton

USS Salt Lake City

USS Pensacola4

USS Chester

Destroyer

Squadron

Four1

9 destroyers

Submarine

Division

Forty-Two3, 4

4 submarines

Destroyer

Squadron

Six

9 destroyers

Submarine

Division

Sixty-Two3, 4

6 submarines

Minecraft

Task Force

Two1

4 minelayers

Notes

1. Left at Pearl Harbor.

2. Flagship of the task force.

3. Elements left at Pearl Harbor.

4. On detached duty.
13

some marine fighters. It was 250 miles away from Pearl Harbor when the 

attack began.

Task Force 3 (see figure 8) was commanded by Vice Admiral William 

Brown and was composed of an aircraft carrier and eight cruisers that 

could have the 2d Marine Division attached for operations. Its mission 

was to capture enemy land objectives and to conduct amphibious operations. Kimmel organized Task Force 12 out of Task Force 3 (the carrier, 

three cruisers, and five destroyers), which on 5 December 1941 left Pearl 

Harbor to deliver bombers to the marines on Midway. It was 500 miles 

southeast of Midway when the attack started.

Figure 8.

Submarine

Division

FortyOne3, 4

Submarine

Division

FortyThree3, 4

Submarine

Division

TwentyOne3, 4

Cdr, Scouting Force

VADM Wilson

Brown

Task Force 3 Organization

7 December 1941

(500 miles southeast of Midway)

Carrier

Division

One(-)

USS Lexington

Cruiser

Division

Four

USS Chicago5

USS Louisville4

USS Portland

USS Indianapolis2, 4

Cruiser

Division

Six

USS Minneapolis4

USS Astoria

USS New Orleans1

USS San Francisco1

Destroyer

Squadron

Five3

9 destroyers 6 submarines 5 submarines 6 submarines

Minecraft

Squadron

Two3, 4

12 minelayers

Notes

1. Left at Pearl Harbor.

2. Flagship of the task force.

3. Elements left at Pearl Harbor.

4. On detached duty.

5. Flagship of Task Force 8.

2d Marine

Division

Submarine

Division

FortyOne3, 4

Submarine

Division

FortyThree3, 4

Submarine

Division

TwentyOne3, 4

Cdr, Scouting Force

VADM Wilson

Brown

Task Force 3 Organization

7 December 1941

(500 miles southeast of Midway)

Carrier

Division

One(-)

USS Lexington

Cruiser

Division

Four

USS Chicago5

USS Louisville4

USS Portland

USS Indianapolis2, 4

Cruiser

Division

Six

USS Minneapolis4

USS Astoria

USS New Orleans1

USS San Francisco1

Destroyer

Squadron

Five3

9 destroyers 6 submarines 5 submarines 6 submarines

Minecraft

Squadron

Two3, 4

12 minelayers

Notes

1. Left at Pearl Harbor.

2. Flagship of the task force.

3. Elements left at Pearl Harbor.

4. On detached duty.

5. Flagship of Task Force 8.

2d Marine

Division
14 

The USMC had a small component on Oahu. Marine Air Group 21 

was at Ewa Field and had Marine Corps Bombing Squadron (VMB)-232, 

Marine Utility Squadron (VMJ)-252, Fixed-Wing Marine Fighter Squadron (VMF)-211 (Rear Echelon), and VMB-231 (Rear Echelon). Together 

these squadrons had10 fighters, 29 bombers, and eight other aircraft. The 

marines had a ground element at Pearl Harbor consisting of the 1st Defense 

Battalion(-), 2d Engineer Battalion, 3d Defense Battalion, and 4th Defense 

Battalion. The marine ground element had 652 men, 12 AA guns, and 36 

machine guns. Sixteen ships (eight battleships, two heavy cruisers, four 

light cruisers, and two auxiliaries) had USMC detachments embarked.

Japanese Organization

Emperor Hirohito of Japan (see figuure 9) was the head of state, not 

the head of government. The Japanese people considered him half god, 

Figure 9.

Commerce

& Industry

Planning

Board

Japanese Government Organization

7 December 1941

Emperor

Hirohito

Prime Minister

Hideki Tojo

War

Navy

Foreign

Affairs

Interior

Imperial HQ

Hideki Tojo

Army

GEN Gen

Sugiyama

Navy

ADM Osami

Nagano

Combined

Fleet

ADM

Isoroku

Yamamoto

Supreme

Military

Council

Board of Marshals

and

Admirals

China

Theater

Fleet

Interior

Forces

Commerce

& Industry

Planning

Board

Japanese Government Organization

7 December 1941

Emperor

Hirohito

Prime Minister

Hideki Tojo

War

Navy

Foreign

Affairs

Interior

Imperial HQ

Hideki Tojo

Army

GEN Gen

Sugiyama

Navy

ADM Osami

Nagano

Combined

Fleet

ADM

Isoroku

Yamamoto

Supreme

Military

Council

Board of Marshals

and

Admirals

China

Theater

Fleet

Interior

Forces
15

half man. He was 41 years old in 1941 and had been emperor for 15 years. 

The emperor presided over all cabinet meetings (although he did not say 

a word during the meetings) and had to approve all matters of state, although he always approved items that were presented to him. Military 

commanders kept him informed on all military subjects. Hirohito had a 

Supreme Military Council and a Board of Marshals and Admirals, but 

these were only advisory boards that had no real authority.

Hideki Tojo, who had served in the army and the government for 36 

years, was the prime minister and the de facto dictator of Japan. Besides 

being prime minister, he was also war minister and chief of the Imperial 

Staff. As prime minister, he had ministers serving underneath him (foreign 

affairs, interior, etc.) and as war minister and chief of the Imperial Staff, 

he dominated military affairs. He believed in the theory of total war and 

believed Japan needed to expand to capture those areas rich in natural resources that Japan lacked. As chief of the Imperial Staff, he had complete 

command of the Japanese military.

Under the Imperial Staff were the army and the navy. The Chief of the 

Army General Staff was General Gen Sugiyama who had been minister of 

war when Japan invaded China, but with Tojo now over him, Sugiyama’s 

powers were limited.

The Chief of the Naval General Staff was Admiral Osami Nagano 

who was the oldest serving officer in the Japanese navy. He had previously 

served as vice chief of the General Staff, navy minister, and commander, 

Combined Fleet. Nagano had three main subordinate elements under him: 

the Interior Forces that controlled the naval districts and ports; the China 

Theater Fleet (composed of a few cruisers and destroyers but mainly 

patrol and gunboats), which was prosecuting the war in China; and the 

Combined Fleet, the main power of the Japanese navy. In December 1941 

the Japanese navy had 10 aircraft carriers, 10 battleships, 38 cruisers, and 

110 destroyers.

Admiral Isoroku Yamamoto commanded the Japanese Combined 

Fleet. Yamamoto had started his career in cruisers (where he lost two fingers at the Battle of Tsushima) and battleships. He later studied at Harvard 

and had served as the Japanese naval attaché in Washington, DC. While 

not a pilot himself, Yamamoto became an air power advocate while commanding an air training base and an aircraft carrier division.

In 1941 the Combined Fleet was a mighty armada consisting of 10 

subordinate fleets and units (see figure 10). Yamamoto kept three battleships and three cruisers under his direct control. The 1st Fleet was the 
16 

Battle Force of the Combined Fleet, charged with destroying any enemy 

fleet. The 2d Fleet was the scouting force, and the 3d Fleet was the blockade and transport force. The 4th and 5th Fleets were charged with defending the Mandated Islands—the Marshalls, Carolines, and Marianas. The 

6th Fleet was the submarine force while all of the seaborne aircraft striking 

power was in the 1st Carrier Fleet. The Southern Fleet was responsible for 

operations south of and excluding China, and the 11th Air Fleet was the 

Figure 10.

Combined Fleet Organization

1941

Combined Fleet

ADM Isoroku

Yamamoto

Fleet HQ/

Fleet Direct

Units

3 battleships

3 cruisers

1st

Fleet

VADM Shiro

Takasu

2 carriers

8 battleships

8 cruisers

31 destroyers

2d

Fleet

VADM Nobutake

Kondo

14 cruisers

32 destroyers

3d

Fleet

VADM Ibo

Takahashi

3 cruisers

Numerous patrol

craft

4th

Fleet

VADM Shigejoshi

Inoue

4 cruisers

8 destroyers

Numerous patrol

craft

5th

Fleet

VADM Boshiro

Hosogaja

5 cruisers

Many patrol

craft

6th

Fleet

VADM M.

Shimizu

29 submarines

1st Carrier

Fleet

VADM Chiuchi

Nagumo

7 carriers

11 destroyers

Southern

Fleet

VADM Dzisaburo

Ozawa

1 cruiser

Few patrol craft

11th

Air Fleet

VADM Nishizo

Cukahara

564 land-based

bombers, transports,

and observation aircraft
17

land-based air-striking force of the Combined Fleet. It had Nell and Betty 

bombers, flying boat observation aircraft, and transports.

As war with the Western Powers became inevitable, Yamamoto reorganized the Combined Fleet to support the numerous operations it was 

tasked to conduct (see figure 11). Built around the 2d Fleet, the Southern 

Expeditionary Force was responsible for operations during the landings in 

Malaysia. The North Philippines Group was built from the 3d Fleet and 

Figure 11.

Combined Fleet Organization

December 1941

Combined Fleet

ADM Isoroku

Yamamoto

Main

Force

2 carriers

7 battleships

2 cruisers

12 destroyers

Southern

Expeditionary

Force

VADM Nobutake

Kondo

2 battleships

11 cruisers

21 destroyers

363 land-based

aircraft

North

Philippines Group

VADM Ibo

Takahashi

5 cruisers

15 destroyers

Numerous patrol/

mine craft

South

Philippines Group

RADM Takeo

Takagi

1 carrier

2 cruisers

12 destroyers

Numerous patrol/

mine craft

South Seas

Force

VADM Shigejoshi

Inoue

8 cruisers

10 destroyers

Numerous patrol/

mine craft

Pearl Harbor

Attack Force

VADM Chiuchi

Nagumo

6 carriers

2 battleships

3 cruisers

9 destroyers

Advanced

Submarine Force

VADM M.

Shimizu

25 submarines

Northern

Force

VADM Boshiro

Hosogaja

6 cruisers

Few patrol/

mine craft

Hong Kong

Landing Force

1 cruiser

2 destroyers

Few patrol/

mine craft
18 

was responsible for operations around the northern half of the Philippine 

invasion. The South Philippines Group was created by taking ships from 

different fleets and was responsible for operations around the southern half 

of the Philippine invasion. The 4th Fleet was the nucleus of the South Seas 

Force; it was to defend the Mandate Islands while also supporting operations during the landings on Guam and Wake Island. The Pearl Harbor Attack Force was built around the 1st Carrier Fleet and was tasked to destroy 

the US Pacific Fleet while the 6th Fleet became the advanced submarine 

force that would conduct reconnaissance, downed pilot picket, and attack 

missions to support the Pearl Harbor operation. The 5th Fleet became the 

Northern Force that was responsible for defending the northern portion of 

the Mandate Islands. The Hong Kong Landing Force was fashioned from 

other fleets and supported the landings at Hong Kong.

Ships

Aircraft Carriers

Navies understood the significance of air power soon after the Wright 

Brothers took their first flight. In 1908 the US Navy sent observers to watch 

the Wright Brothers demonstrate their plane to the US Army, and the Navy 

asked the Wright Brothers to create an aircraft that could be launched from 

a ship, but they were not interested. The Navy turned to Glenn Curtiss who 

accepted the project. On 14 November 1910 Eugene B. Ely, an employee 

of Curtiss, launched his plane from a specially constructed platform on the 

light cruiser USS Birmingham. After this successful test, naval aviation 

prospered. Curtiss soon invented a plane and ship system whereby a seaplane could land next to a ship, be winched aboard, and be lowered back 

to the sea to take off again.

Figure 12. HMS Argus.

Naval Historical Center
19

On 19 July 1918 the British conducted the first carrier strike in history. Seven planes took off from the HMS Furious and attacked Zeppelin 

sheds at Tondern, Germany. The planes, however, had to ditch in the ocean 

because the Furious’ deck was not set up for landing. The HMS Argus was 

the first true carrier, and it was launched in November 1918.

In 1922 the United States launched its first aircraft carrier, the USS 

Langley, which was a converted collier. The United States added two 

more carriers, the Lexington and Saratoga, in the 1920s by converting 

battle cruisers that were under construction. In 1934 the US Navy commissioned the USS Ranger, the first US aircraft carrier built as a carrier 

from the keel up. By December 1941 the United States had seven fleet 

carriers and one escort carrier. Three of these carriers were assigned to 

the Pacific Fleet.

The Japanese also learned to incorporate aircraft carriers into their 

fleet. Their first carrier was the IJN Wakamiya, which was a seaplane tender, but late in its career, it received a platform from which to launch aircraft. Japan also converted battle cruisers into aircraft carriers, and in 1925 

it launched the Akagi, soon followed by the Kaga. By December 1941 the 

Japanese had 10 fleet carriers.

Japanese Aircraft Carriers

Converted from a battle cruiser during construction.

Completed in 1927; overhauled 1935-38.

Displacement: 36,500 tons

Maximum speed: 31 knots

Crew: 2,000

Aircraft: 72 (91 in an emergency)

Naval Historical Center

Figure 13. Akagi.
20 

Converted from a battle cruiser during construction.

Completed in 1928; overhauled 1934-35.

Displacement: 38,200 tons

Maximum speed: 28 knots

Crew: 2,016

Aircraft: 72 (90 in an emergency)

Converted from a flight deck cruiser during construction.

Completed in 1939.

Displacement: 18,800 tons

Maximum speed: 34 knots

Crew: 1,100

Aircraft: 63 (71 in an emergency)

Converted from a flight deck cruiser during construction.

Completed in 1939.

Displacement: 20,250 tons

Maximum speed: 34 knots

Crew: 1,101

Aircraft: 63 (73 in an emergency)

Naval Historical Center

Naval Historical Center

Figure 14. Kaga.

Figure 15. Soryu.

Figure 16. Hiryu.

Naval Historical Center
21

Completed in August 1941.

Displacement: 36,000 tons

Maximum speed: 34 knots

Crew: 1,660

Aircraft: 72 (84 in an emergency)

Completed in September 1941.

Displacement: 36,600 tons

Maximum speed: 34 knots

Crew: 1,660

Aircraft: 72 (84 in an emergency)

Figure 17. Shokaku.

Figure 18. Zuikaku.

Naval Historical Center Naval Historical Center
22 

American Aircraft Carriers

Converted from a battle cruiser during construction.

Completed in 1928.

Displacement: 41,000 tons

Maximum speed: 34 knots

Crew: 2,122

Aircraft: 81

Converted from a battle cruiser during construction.

Completed in 1928.

Displacement: 33,000 tons

Maximum speed: 34 knots

Crew: 2,111

Aircraft: 81

Figure 19. USS Lexington, CV-2.

Naval Historical Center

Naval Historical Center

Figure 20. USS Saratoga, CV-3.
23

Completed in 1938.

Displacement: 19,800 tons

Maximum speed: 33 knots

Crew: 2,919

Aircraft: 90

Battleships

Battleships had been the mainstay of fleets for generations. As early 

as the 1850s, nations had been designating their main, big gun ships as 

“battleships.” As technology improved, nations kept building larger, better-armored ships, and technology also allowed larger guns to be produced 

for these heavily armored but slow ships. An example of this era of ships 

is the USS Ohio, which was completed in 1904, displaced 12,000 tons, had 

a maximum speed of 18 knots, and was armed with four 12-inch guns, 16 

6-inch guns, and other smaller weapons.

At the Battle of Tsushima in 1905, the opponents started firing at 

19,000 yards, questioning whether the secondary armaments (6-, 8-, and 

9-inch guns) were needed on battleships. Because of this phenomenon, the 

United States and England began work on classes of all “big gun” battleships. The British won the race when they completed the HMS Dreadnaught in 1906. It displaced 18,000 tons, had a maximum speed of 21 

knots (due to steam turbine engines), and was armed with 10 12-inch guns. 

Its speed, armor, and firepower made all previous battleships obsolete. Nations scrambled to build all “big gun” battleships so that by 1941 nations 

were building battleships that displaced 35,000 tons, could reach speeds of 

27 knots, and had 16-inch guns.

Figure 21. USS Enterprise, CV-6.

Naval Historical Center
24 

Japanese Battleships

Built as a battle cruiser; converted to a battleship during overhaul.

Completed in 1914; overhauled 1936-40.

Displacement: 29,300 tons

Maximum speed: 27 knots

Crew: 1,221

Armament: eight 14-inch guns, 16 6-inch guns, eight 5-inch AA guns

Built as a battle cruiser; converted to a battleship during overhaul.

Completed in 1915; overhauled 1927-30, 1935-36.

Displacement: 32,000 tons

Maximum speed: 28 knots

Crew: 1,200

Armament: eight 14-inch guns, 16 6-inch guns, eight 5-inch AA guns

Figure 22. Hiei.

Naval Historical Center Naval Historical Center

Figure 23. Kirishima.
25

American Battleships

Completed in 1916; overhauled 1927-30.

Displacement: 27,500 tons

Maximum speed: 20 knots

Crew: 1,552

Armament: 10 14-inch guns, 24 5-inch guns

Completed in 1916; overhauled 1927-29.

Displacement: 27,500 tons

Maximum speed: 21 knots

Crew: 1,552

Armament: 10 14-inch guns, 24 5-inch guns

Naval Historical Center

Naval Historical Center

Figure 25. USS Oklahoma, BB-37, Nevada class.

Figure 24. USS Nevada, BB-36, Nevada class.
26 

Completed in 1916; overhauled 1940-41.

Displacement: 31,400 tons

Maximum speed: 21 knots

Crew: 1,620

Armament: 12 14-inch guns, 24 5-inch guns

Completed in 1916; overhauled 1929-31.

Displacement: 31,400 tons

Maximum speed: 21 knots

Crew: 1,588

Armament: 12 14-inch guns, 24 5-inch guns

Completed in 1920.

Displacement: 33,100 tons

Maximum speed: 21 knots

Crew: 1,625

Armament: 12 14-inch guns, 16 5-inch guns

Figure 26. USS Pennsylvania, BB-38, Pennsylvania class.

Figure 27. USS Arizona, BB-39, Pennsylvania class.

Figure 28. USS Tennessee, BB-43, Tennessee class.

Naval Historical Center

Naval Historical Center

Naval Historical Center
27

Completed in 1921; overhauled 1929-30.

Displacement: 32,300 tons

Maximum speed: 21 knots

Crew: 1,623

Armament: 12 14-inch guns, 16 5-inch guns

Completed in 1921.

Displacement: 32,600 tons

Maximum speed: 21 knots

Crew: 1,623

Armament: eight 16-inch guns, 18 5-inch guns

Completed in 1923.

Displacement: 33,590 tons

Maximum speed: 21 knots

Crew: 1,626

Armament: eight 16-inch guns, 26 5-inch guns

Naval Historical Center

Figure 29. USS California, BB-44, Tennessee class.

Figure 30. USS Maryland, BB-46, Colorado class.

Figure 31. USS West Virginia, BB-48, Colorado class.

Naval Historical Center

Naval Historical Center
28 

Cruisers

Cruisers were lightly armored, heavily armed, fast ships designed 

to screen formations and to scout out enemy fleets. Their survivability 

depended on speed, not armor. Japan developed classes of battle cruisers 

armed with 14-inch guns, but they were converted to battleships during 

overhauling. The United States and Japan had each decided to build a 

new class of battle cruiser (lightly armored but armed with 14- or 16-inch 

guns), but the limitations of the Washington Naval Treaty of 1922 only allowed cruisers to displace 10,000 tons or less so cruisers became smaller 

and more lightly armed. By 1941 Japan had 38 cruisers, and the US Pacific 

Fleet had 21 cruisers. Each side had different classes, and a sample of a 

cruiser from each side follows.

Completed in 1926.

Displacement: 10,507 tons

Maximum speed: 33 knots

Crew: 625

Armament: six 8-inch guns, four 4.7-inch guns,

 eight 24-inch torpedo tubes, 42 25mm guns

Completed in 1923.

Displacement: 9,950 tons

Maximum speed: 33 knots

Crew: 708

Armament: nine 8-inch guns,

 eight 5-inch guns, 16 40mm guns

Figure 32. Japan’s Furutaka.

Figure 33. USS New Orleans, CA-32, New Orleans class.

Naval Historical Center

Naval Historical Center
29

Destroyers

Destroyers had been around since the 1890s. Originally named “Torpedo Boat Destroyers,” these ships were small, fast, and armed with 

rapid-firing guns to destroy enemy torpedo boats. With the invention of 

the submarine, destroyers took on the antisubmarine mission, and the 

name of this type of ship was shortened to “destroyer.” By 1941 navies 

used destroyers as screening vessels, scouting vessels, anti-torpedo-boat 

ships, and antisubmarine ships. By 1941 Japan had 110 destroyers, and the 

US Pacific Fleet had 53. Each side had different classes, and a sample of a 

destroyer from each side follows.

Completed in 1928.

Displacement: 2,090 tons

Maximum speed: 38 knots

Crew: 197

Armament: six 5-inch guns,

 18 depth charges, nine 24-inch torpedo tubes

Completed in 1928.

Displacement: 1,850 tons

Maximum speed: 36.5 knots

Crew: 158

Armament: four 5-inch guns, 12 21-inch torpedo tubes

Figure 34. Japan’s Amagiri.

Figure 35. USS Helm, DD-388, Bagley class.

Naval Historical Center

Naval Historical Center
30 

Submarines

Navies had experimented with submarines since the 1860s, and as 

technology increased, the submarine’s capabilities improved greatly. During World War I, Germany sank more than 5,000 Allied ships using their 

submarines, but these era submarines were limited by range, so postwar 

improvements led to submarines that could cross the Atlantic or Pacific 

Oceans easily and return.

The United States started seriously working to acquire a submarine 

fleet in the late 1890s, and in 1900 it launched its first submarine. From 

1900-41 the United States continued to improve its submarine fleet.

In 1905 Japan was locked in combat with Russia and looked for asymmetric ways to defeat the superior Russian navy and started acquiring 

submarines. Their first five submarines were purchased from the United 

States. After the war with Russia, Japan developed its own submarines 

and continued to improve them, developing numerous types including 

seaplane carriers, mine warfare submarines, and midget submarines. By 

1941 Japan had 65 fleet submarines, and the US Pacific Fleet had 23. Each 

side had different classes, and a sample of a submarine from each side 

follows.

Completed in 1934.

Displacement: 1.400 tons

Maximum speed: 23 knots surface, 8 knots submerged

Crew: 84

Armament: six 53-centimeter (cm)

 torpedo tubes, one 10cm gun

Figure 36. Japan’s I-68.

Naval Historical Center
31

Completed in 1938.

Displacement: 46 tons

Maximum speed: 23 knots surface,

 19 knots submerged

Crew: 2

Armament: two 53cm torpedo tubes

Completed in 1934.

Displacement: 1.475 tons

Maximum speed: 20 knots surface, 9 knots submerged

Crew: 65

Armament: 10 21-inch torpedo tubes, one 3-inch gun

Figure 37. Japan’s HA-19.

Figure 38. USS Tautog, SS-199, Tambor class.

Naval Historical Center Naval Historical Center
32 

Aircraft

Fighters

Military use of aircraft predates the invention of the airplane. As early 

as the 1860s, nations used balloons to conduct reconnaissance of enemy 

positions. Militaries first employed aircraft in observation roles to gain 

valuable information on the enemy, and during World War I nations started 

arming their aircraft so they could destroy any enemy observation aircraft 

that appeared. These early armed aircraft were termed “fighting scouts.” 

They were plagued with very short range and, as such, were defensive 

aircraft. As aviation technology improved during the war, nations were 

able to increase their fighters’ range, and they were used to attack ground 

targets. Air superiority became a prerequisite for any operation; militaries wanted control of the air so they could prevent the enemy from using 

their aircraft to attack and observe while they used their own to attack the 

enemy. Allied air superiority over the Central Powers was an important 

aspect of their victory in World War I.

After World War I technological advances improved the fighter’s performance as metal replaced wood in aircraft structure and aerodynamics 

improved to allow the monoplane to replace the biplane. Other improvements included adding optical sights, more and bigger machine guns, radio 

communications, and retractable landing gear. By 1941 fighters were both 

an effective offensive and defensive weapon. In the offensive role, fighters 

protected other aircraft, and if there were no enemy fighters, they could be 

employed to strafe targets. In the defensive role, fighters could remain at 

their base, and once a threat was detected, take off and attack the enemy.

Japanese Fighter

User: Army and Navy

Crew: 1

Speed: 340 miles per hour (mph)

Range: 1,160 miles

Armament: two 20mm cannons, two 7.7mm machine gunsNaval Historical Center

Figure 39. A6M2 Zero fighter.
33

American Fighters

User: Army

Crew: 1

Speed: 362 mph

Range: 850 miles, 1,200 with auxiliary tank

Armament: six .50-caliber machine guns,

 up to 700 pounds (lb) of bombs

User: Army

Crew: 1

Speed: 313 mph

Range: 830 miles

Armament: two .30- or .50-caliber machine guns

US Air Force Museum

Figure 40. P-40 Warhawk.

Figure 41. P-36 Hawk.

US Air Force Museum
34 

User: Navy and Marine Corps

Crew: 1

Speed: 320 mph

Range: 770 miles

Armament: six .50-caliber machine guns, 200 lb of bombs

Bombers

As aircraft took on the role of attack, pilots soon carried small bombs 

with them to drop on the enemy. Nations saw the utility of being able to 

deliver bombs from the air and developed aircraft whose primary mission 

was to drop bombs. Dirigibles were employed to deliver bombs, but soon 

technological advances allowed the construction of larger aircraft that 

could deliver bigger payloads. During World War I, large bombers were 

used to attack enemy homelands. The Germans used the Gotha bomber to 

bomb London while the British used the Handley-Page bomber to bomb 

Germany. After the war, technology allowed for bigger and better bombers 

as aerodynamics and engine improvements led to larger bombers with bigger payloads and the ability to carry machine guns for self-protection and 

optical sighting improvements led to increased bombing accuracy.

Tests during the interwar period led many innovators to believe that 

air power could attack and destroy ships, a fact not lost on farsighted 

naval officers. Navies developed bombers that could be launched from 

ships, and while smaller than land-based bombers, seaborne bombers 

could deliver devastating strikes against ships. Navies also developed dive 

bombers—airplanes designed to carry smaller bombs that started their attack high above the target, then dove on their target in a steep dive, thus 

increasing accuracy. Torpedoes had devastating effects against shipping Naval Historical Center

Figure 42. F4F3 Wildcat.
35

in World War I, so navies developed airplanes that could skim across the 

water and deliver torpedoes against enemy ships. Some navies also used 

these torpedo planes as high-level bombers because they were able to 

carry heavy loads.

Japanese Bombers

User: Navy

Crew: 3

Speed: 235 mph

Range: 683 miles

Armament: two 7.7mm machine guns in cowling,

 one 7.77mm machine gun in rear cockpit,

 one 1,750-lb torpedo or 1,750 lb of bombs

User: Navy

Crew: 2

Speed: 281 mph

Range: 874 miles

Armament: two 7.7mm machine guns over the engine,

 one 7.7mm machine gun in rear cockpit, one 550-lb bomb

Naval Historical Center Naval Historical Center

Figure 43. B5N2 Kate torpedo/high-level bomber.

Figure 44. D3A Val dive bomber.
36 

American Bombers

User: Army

Crew: 6

Speed: 292 mph

Range: 3,000 miles

Armament: seven .50-caliber machine guns, 6,000 lb of bombs

User: Army

Crew: 6

Speed: 217 mph

Range: 1,200 miles

Armament: three .30-caliber machine guns,

 4,400 lb of bombs

Figure 46. B-18 Bolo.

Figure 45. B-17B Flying Fortress.

US Air Force Museum US Air Force Museum
37

User: Navy

Crew: 7 to 9

Speed: 189 mph

Range: 2,900 miles

Armament: two .50-caliber machine guns,

 4,000 lb of bombs/depth charges/torpedo

User: Navy and Marine Corps

Crew: 2

Speed: 255 mph

Range: 1,345 miles

Armament: two .50-caliber machine guns forward,

 two .30-caliber machine guns in rear cockpit,

 1,600 lb of bombs

Naval Air Station, Jacksonville Naval Historical Center

Figure 47. PBY-5 Catalina.

Figure 48. SBD-2 Dauntless dive bomber.
38 

User: Navy

Crew: 2 to 3

Speed: 207 mph

Range: 700 miles

Armament: one .50-caliber machine gun forward,

 one .30-caliber machine gun in rear cockpit,

 1960 lb of bombs/torpedoes

Strategy

Despite the fact that Japan had been an ally during World War I, 

American war planning in the interwar years focused on war with Japan, 

and Japanese planning focused on the United States. Responsibility for US 

joint strategic war plans fell to the Joint Board, which had been organized 

in 1903. From its inception through World War I, the Joint Board was 

ineffectual and produced little of strategic value, so it was reorganized 

in 1919 to provide some real jointness to war planning. The Board now 

consisted of six members—the Army Chief of Staff, Chief of Naval Operations (CNO), their deputies, and their chiefs of war plans. Additionally, 

the Joint Planning Committee was formed to give the Joint Board a staff 

for joint war planning, and the Army and Navy each provided four officers from its War Plans Division to conduct the detailed preparations of 

joint plans. The Joint Planning Committee started work on a series of war 

plans that focused on fighting one enemy at a time. The plans were named 

“color plans” because each potential enemy was a different color—orange 

for Japan, red for England, etc. The plans the Joint Planning Committee 

produced were the basis for developing subordinate supporting plans for 

each of the services.

The original series of Orange Plans for war against Japan called for Naval Historical Center

Figure 49. TBD-1 Devastator torpedo/high-level bomber.
39

offensive naval war against Japan. To accomplish this, the Navy needed a 

base in the Far East to service the entire US Fleet, and Manila provided the 

only capable port west of Pearl Harbor. Therefore, the Army’s responsibility became to defend and hold Manila Bay until the US Fleet arrived with 

Army reinforcements.

Diplomatic actions hindered US planning for war with Japan during 

the 1920s and 1930s. In 1922 the United States signed the Five Power Naval Treaty that called for the United States, Japan, Great Britain, France, 

and Italy to not fortify any of their Far Eastern possessions. Japan never 

had plans to fortify any of its positions in the Mandate Islands, and this 

treaty ensured that the Philippines, Guam, and Hong Kong could not become fortresses in Japan’s backyard.

Politicians and diplomats, in response to the devastation of World War 

I, looked for ways to prevent war, and treaties and agreements seemed like 

the answer. The Washington Naval Conference of 1922 led to an agreement whereby the United States, Great Britain, and Japan would limit their 

capital ships based on the ratio 5-to-5-to-3. On paper, this seemed like a 

bargain for the United States and Britain because their navies could be 40-

percent larger than Japan’s. The problem was that the United States and 

Britain had to reduce their navies (the United States scrapped 15 battleships and cruisers that had been under construction) while the Japanese 

had to build up to get to their “limitation.” With the stroke of a pen, Japan 

reduced the size of the US Navy while being allowed to increase the size 

of its own navy.

While writing joint war plans was important to US war planners, by 

1937 they realized that their basic assumption of having to fight only one 

enemy at a time was doubtful. In 1936 and 1937 Japan, Germany, and Italy 

had executed a number of agreements that created what became known 

as the Axis Alliance. The possibility of having to simultaneously fight in 

the Atlantic and Pacific forced planners to reassess their assumptions. The 

Joint Board and the Joint Planning Committee focused on the problem, 

and in 1939 they developed guidelines for a new series of war plans called 

the “Rainbow” plans. This name signified that multiple potential enemies 

were involved, thus different color plans were combined. The planners developed five Rainbow war plans, numbered one through five, all of which 

first provided for the defense of the Western Hemisphere in accordance 

with the Monroe Doctrine (see figure 50).

Rainbow 1 assumed the United States would fight without allies and 

would focus action in the Atlantic while maintaining a strategic defensive 
40 

in the Pacific. When the situation in the Atlantic allowed, the United States 

would concentrate in the Pacific. Rainbow 2 assumed that the United 

States would fight with Britain and France and, therefore, could focus on 

the Pacific. Rainbow 3 assumed that the United States would fight without 

allies and would concentrate on the Pacific first. Rainbow 4 was similar to 

Rainbow 1—the United States would not have any allies and would have 

to focus on the Atlantic—but this plan called for the Army to be sent to 

South America for operations. Rainbow 5 specified that the United States 

would be allied with Britain and France, and would ensure the defeat of 

Germany before concentrating on Japan.

With the start of World War II and after the fall of France, the US planners reconsidered all of their alternatives. Western Europe had fallen, Britain was barely hanging on, and if it fell, Germany and Japan could attack 

the Western Hemisphere. Reinforcing England seemed to be the logical 

priority in any war situation. CNO Admiral Harold Stark produced what 

has been called Plan Dog (because the recommendation was contained in 

paragraph D, “Dog,” in the phonetic alphabet of the time). Stark’s analysis 

Rainbow War Plans

Primary Secondary

Plan Allies Area Area

1 None Atlantic Pacific

2 Britain, France Pacific Atlantic

(limited)

3 None Pacific Atlantic

4 None South Pacific

Atlantic

5 Britain, France Atlantic Pacific

Rainbow War Plans

Primary Secondary

Plan Allies Area Area

1 None Atlantic Pacific

2 Britain, France Pacific Atlantic

(limited)

3 None Pacific Atlantic

4 None South Pacific

Atlantic

5 Britain, France Atlantic Pacific

Figure 50. Rainbow war plans.
41

indicated that it was key to the United States to ensure Britain did not fall. 

If it did, Germany and Italy would likely expand into the Western Hemisphere, and retaining England, as a staging base for future land actions 

against the European continent, was imperative. Stark thought that Britain 

did not have the manpower and was too weak economically to fight alone 

so he recommended that the United States assist Britain in any way possible. His recommendations were accepted, and the Atlantic became the 

primary theater of operations.

Japan had desired to be the most powerful nation in the Far East since 

the 1890s. As part of that plan, Japan had to expand to acquire areas that 

were rich in natural resources not available in Japan and to form a protective outer ring away from the home islands. With victories over the 

Russians and Chinese in the late 1890s/early 1900s, Japan had obtained 

Formosa, Korea, the Kuril Islands, and parts of Manchuria. As an ally at 

the end of World War I, Japan was mandated from Germany possession of 

the Marshall Islands, the Caroline Islands, and the Mariana Islands. Japan 

thought the best way to be the foremost power of the Far East was through 

economics, so the United States, the real economic competitor in the area, 

became the most likely adversary.

Despite diplomatic successes (the Five-Power Naval Limitation 

Treaty, Washington Naval Conference, etc.), Japan was still militarily 

inferior to the United States and had to develop a plan for war that ensured 

victory. Because of the limitations of the Washington naval treaty, the 

Japanese looked for ways to gain any naval advantage. Its submarine 

fleet was wanting (and there were no treaty limitations on submarines), 

so Japan concentrated on improving and increasing it. Additionally, the 

treaty limited the tonnage of cruisers and battleships but allowed ships 

under construction to be converted to aircraft carriers of limited tonnage 

(of which the Japanese underreported the size of its new carriers). With 

improved submarine and aircraft carrier capabilities, but with an inferior 

capital ship ratio, Japan developed the concept of “Kantai Kessen” 

(decisive fleet battle).

Kantai Kessen assumed that any war with the United States would 

be primarily a naval war. Therefore, Japan wanted the fight to be near the 

Japanese home islands. They envisioned the United States sailing a large 

fleet toward Japan. Along the way Japanese submarines would track and 

attrit the US fleet. The Americans would have to bypass Japanese bases on 

the Mandate Islands, which could then be used to attack the fleet from the 

air and would also be astride the lengthening US line of communication. 

As the now-attrited US fleet approached the Japanese home islands, the 
42 

main Japanese fleet, supported by land-based air power, would fight and 

defeat the US fleet.

Operational

In response to the Rainbow plans, the US Pacific Fleet reorganized 

(see figure 5). Rainbow 5 was the most likely plan to be executed, so in 

July 1941 Kimmel issued his own plan for executing Rainbow 5. Since 

the United States’ main effort was the Atlantic, Kimmel developed a plan 

that defended Hawaii and the West Coast while simultaneously setting the 

conditions for future operations. At the outbreak of war, the Pacific Fleet 

would sweep the ocean of all Japanese shipping west of Hawaii, conduct 

reconnaissance and raids on the Marshall Islands, move the 2d Marine 

Division to Hawaii, and prepare to invade the Marshall Islands. Once 

these tasks were completed, the Pacific Fleet would seize Truk Island in 

the Marshall Islands to use as an advanced fleet base in subsequent operations. Eventually, the Pacific Fleet would seize all of the Marshall and the 

Caroline Islands. Once the Pacific Fleet had seized the Marshall and Caroline Islands, it would develop plans for subsequent operations. Other tasks 

assigned to the Pacific Fleet were defending Guam, protecting the sea 

lines of communication, and defending territory in the Pacific to prevent 

Japanese expansion into the Western Hemisphere. The purpose of these 

operations was to divert enemy strength away from the western Pacific to 

“support the forces of the associated powers in the Far East.”

The Japanese developed plans for executing Kantai Kessen, and the 

Combined Fleet was organized to execute the plan (see figure 10). The 

6th Fleet of the Combined Fleet had three types of submarines to support 

Kantai Kessen. Scouting submarines equipped with seaplanes would locate and maintain contact with the US fleet. Command submarines would 

coordinate raids by attack submarines and cruisers from the 2d Fleet. As 

the US fleet steamed west, it would be attacked from the air by land-based 

bombers from the 11th Air Fleet stationed in the Mandate Islands. The 

1st Carrier Fleet’s aircraft would locate the American carriers and attack 

them with dive bombers to destroy their flight decks, attempting to prevent American air operations. As the US fleet neared the home islands, 

more submarines would lay minefields and launch midget submarines to 

continue to attrit the enemy. Once within range of Japan, more land-based 

aircraft of the 11th Air Fleet would attack the US fleet. The 1st Fleet’s 

battleships and heavy cruisers would clear away any US screening forces 

so that swift light cruisers and destroyers could sweep in for massed torpedo attacks. At this point, the battleships and heavy cruisers would join 

the fight to finish off the American fleet.
43

Tactics

Naval tactics of the 1940s were based on time-tested principles of getting as much steel on a target as fast as possible. Fleets had a submarine 

component whose mission was to locate and track enemy fleets, with the 

secondary mission of attacking smaller combat vessels or logistics ships. 

Scouting forces were a major part of any fleet, and their purpose in the 

offense was to locate and attack the enemy fleet with high-speed cruisers 

and destroyers using torpedoes. Additionally, the scouting forces’ speed 

allowed them to get ahead of an enemy’s main force to “cross the T” (the 

process of steaming in line across the front of an enemy line, thus allowing 

you to maximize fire on the enemy while he cannot bring all of his guns to 

bear on you. (See figure 51.)

In the defense, the scouting force would protect the main fleet by preventing the enemy’s scouting force from locating 

and/or attacking the main 

fleet and attacking the enemy main fleet as it closed. 

Aircraft carriers were used 

to launch aircraft to locate 

enemy fleets and to control 

the gunfire of the battleships 

and cruisers. Eventually, 

dive bombers were developed to strike an enemy carrier’s flight deck so it could 

not launch its own aircraft. 

Torpedo planes could be 

used in conjunction with 

torpedo attacks by cruisers 

and destroyers. The battle 

force of any fleet was the 

main fighting unit of any 

navy. Large battleships and 

battle cruisers, supported by 

faster light cruisers and destroyers, would maneuver to 

gain position on the enemy. 

The preferred tactic was to 

cross the T, but doctrine Figure 51.

“Crossing the T”
44 

existed for parallel attacks, either steaming in the same direction or sailing opposite the enemy (see figure 52). The keys to success for any naval 

engagement were maneuvering to gain an advantageous position on your 

enemy and the crews’ gunnery skills; those who could hit targets from 

great distances would win the battle.

Figure 52.

Main Force

or

Main Force

or
45

Logistics

Due to the distances involved in the Pacific, logistics was a concern to both 

sides. The US fleet had its main ports and naval yards along theUS West 

Coast at Puget Sound and San Diego. These yards could resupply, refit, 

repair, and completely overhaul ships. In 1940 Pearl Harbor was the home 

base of the Hawaiian Detachment (a carrier, a cruiser, and some destroyers), but it possessed only limited capabilities. Ships could refit, refuel, 

and rearm, but major repairs and overhauls still had to be accomplished on 

the West Coast. All across the Pacific, the United States maintained small 

naval bases at such places as Johnston Island, Midway, Palmyra, American Samoa, Wake Island, and Guam. Each of these small bases maintained 

an airfield, and some served as submarine bases and/or refuel and rearm 

points. The Navy Base at Subic Bay in the Philippines was another of the 

Navy’s major bases, but it also only possessed limited capability to refuel, 

rearm, and repair ships of the fleet.

In 1940 the Pacific Fleet shifted its home port from the West Coast 

to Pearl Harbor. Immediately, work was started to convert Pearl Harbor 

into a base that would be capable of supporting the Pacific Fleet with all 

services required except major repair and overhaul. New docks, dry docks, 

and fuel tanks were added to the facility, and by 1941 Pearl Harbor was a 

major base.

The major limitation of ships of the 1930s and 1940s was the amount 

of fuel they could carry. The ships could carry enough food and water for 

the sailors, but they needed to stop to refuel. Destroyers had the shortest 

range and could travel about 6,000 nautical miles at 15 knots before refueling, while battleships could range 13,000 miles and carriers 15,000 miles. 

Due to the limited ranges, the Navy had to have bases all across the Pacific 

to service its fleet. In 1941 ships were able to refuel at sea, but it was not a 

common practice so the Navy still depended on bases to refuel their ships.

Everything the Pacific Fleet (and the smaller Asiatic Fleet in the 

Philippines) used had to be moved by ship from CONUS to the servicing 

bases. As part of its organization, the Pacific Fleet had Task Force 4, which 

was responsible for organizing, training, and developing the bases (Pearl 

Harbor, Midway, Wake) and providing service to those fleet units engaged 

in operations. Additionally, Task Force 15 was to secure shipping coming 

from the United States.

The Navy had limited shipping assets to support its fleet. In 1941 the 

Navy had the following logistics ships (numbers in parentheses are ships 

supporting the Pacific Fleet):
46

Oilers 29 (11)

Munitions ships 4 (2)

Cargo ships 22 (5)

General stores ships 3 (2)

Provisions ships 9 (4)

Transports 37 (8)

Hospital ships 2 (1)

Due to the distances involved, logistics was critical to Japan. Japan 

maintained its ports and navy yards throughout the home islands. They 

maintained larger bases at locations, including Yokosuka, Kure, Sasebo, 

Maizuru, and Bako. These bases could provide all required services for 

ships up to and including overhaul. There were many smaller yards and 

bases throughout the home islands that provided more limited support. 

Japan, like the United States, depended on forward bases for their ships. 

Their base on Truk Island was the most advanced, with services including 

refuel, rearming, and repairing. Other bases away from the home islands 

were Saigon and Formosa. Like the United States, Japan’s ships could 

also refuel while under way, but it was not a practiced skill and was very 

rarely used.

The Japanese navy had built a lot of ships, but it, like the United 

States, did not have enough logistics ships to properly support its fleets. 

In 1941 the Japanese navy had the following logistics ships (numbers in 

parentheses are ships supporting the Combined Fleet):

Oilers 37 (31)

Munitions ships 1 (1)

Cargo ships 7 (1)

General stores ships 11 (3)

Provisions ships 12 (12)

Transports 64 (59)

Hospital ships 5 (4)
47

II. Pearl Harbor Campaign Overview

In July 1853 Commodore Matthew Perry, in command of four US 

Navy ships, arrived at Edo (now Tokyo) under orders from President Millard Fillmore to make contact with the Japanese to open commercial relations with the reclusive nation. The Japan of 1853 was much like the Japan 

of 1653, a feudal nation of many different clans headed by the warrior 

class samurai, with a shogun (meaning “general”) leader with dictatorial 

powers. The emperor was the head of state (but not of the government) 

and Japan’s religious leader, but he had no real power. Starting in 1653 the 

shoguns had kept Japan in isolation; missionaries who attempted to enter 

the country were killed, traders were driven off, and shipwrecked seamen 

were imprisoned.

When Perry entered the bay at Edo, the Japanese leaders observed 

his ships belching smoke and bristling with modern cannons, and while 

impressed with the show of force, the Japanese would not agree to Perry’s 

terms. He departed, determined to return to complete the mission.

In February 1854 Perry did return, but this time he brought seven 

warships and a large contingent of marines. Perry came ashore with a 

marine band leading and immediately started negotiating a treaty with the 

Japanese. The shogun was intimidated by the power of the United States 

and reluctantly agreed to the Treaty of Kanagawa, which was signed on 31 

March 1858. The treaty called for friendship between the nations, opening 

two ports for the United States to use, safety guarantees for shipwrecked 

seamen, and allowances for the United States to acquire supplies and provisions from the Japanese. Soon, other nations arrived to negotiate treaties 

with Japan, and the once isolationist country was now thrown open to the 

West.

However, some of the clans in western Japan were upset with the 

shogun’s inability to keep Japan isolated, which led to internal strife for 

control of the country. What were initially small clashes between the 

shogun’s forces and the western clans led to full-scale war in 1868. For 

seven months the western clans battled the shogun’s supporters, but on 

4 July 1868 the western clans won the Battle of Veno and control of the 

nation. They immediately restored the emperor to power and effectively 

ended the feudal era.

The new government realized that Japan, now open to the West, had 

to modernize to achieve equality and immediately implemented measures 

to attain this goal. Feudalism and its associated samurai class were abolished, modern administrative zones within the country were established, 
48 

an Imperial Army was raised through conscription, and an Imperial Navy 

was created by purchasing British ships. To support these efforts, the government organized a banking system that allowed commerce to flourish, 

created a national school program that preached loyalty to the emperor, 

and significantly improved the nation’s infrastructure. By 1890 Japan was 

a regional power in the Far East.

In need of raw materials and new markets, Japan fought China in the 

Sino-Japanese War in 1894-95. Fought in Korea and Manchuria, the Imperial Army and Imperial Navy won numerous victories, forcing China to 

sue for peace, in which China ceded Korea and Formosa and paid a large 

indemnity. Russia now intimidated the defeated Chinese and was able to 

acquire Port Arthur and the Chinese Eastern Railway, which sowed the 

seeds for future conflict with the Japanese.

Starting in 1900 Japan prepared for war with Russia to ensure it 

dominated the area and to extract revenge for Russian meddling after the 

Sino-Japanese War. On 8 February 1904, before war was declared, Japan 

attacked the Russian Far East fleet in Port Arthur with torpedo boats, causing extensive damage. The now superior Japanese fleet trapped the weakened Russian fleet in the port. Japanese ground troops laid siege to Port 

Arthur on 25 May 1904 and finally forced the Russian garrison and fleet 

to surrender on 2 January 1905. Meanwhile, the Russians had decided to 

move their Baltic fleet to the Far East and after a horrific journey, the numerically superior, but qualitatively inferior, Russian Fleet was destroyed 

at the Battle of Tsushima on 27 May 1905. Admiral Heihachiro Togo, the 

fleet commander, became a national hero, and a young ensign named Isoroku Yamamoto, who was serving on one of the Japanese cruisers, was 

wounded, losing two fingers in the fight. The United States brokered a 

peace treaty whereby Russia gave up its interests in the area, including 

Port Arthur. Japan was now the clear power in the Far East.

Japan joined the Allies during World War I, a prudent act for which Japan reaped great rewards. The other allied nations required materials, and 

Japanese industry flourished as it worked to meet the allied war demands. 

Japan occupied the German possessions of the Mariana, Caroline, and 

Marshall Islands, which were mandated to Japan after the war. While only 

suffering 300 military deaths, Japan expanded its empire to the Central 

Pacific and also became an industrial power.

After the carnage of World War I, nations were seeking ways to avoid 

future slaughter, and treaties were completed to accomplish this. Between 

1921 and 1934 various nations signed seven major disarmament treaties, 
49

but the Washington Naval Conference, 1921-22, had the greatest impact 

on Japan and the United States as they moved toward World War II. The 

major points of the resulting treaty were a capital ship tonnage ratio of 5-

to-5-to-3 for the United States, Great Britain, and Japan; a 10-year moratorium on capital ship construction; and a prohibition on constructing and 

improving fortifications of Pacific possessions. On paper this treaty looked 

like a huge triumph for the United States, but Japan was the true victor.

The treaty allowed the United States to have 525,000 tons of capital 

ships while Japan could only have 315,000 tons. However, the United 

States had to decommission ships and stop constructing new ships (15 

battleships and battle cruisers) to stay within the limits. As a result, the 

newest US battleship at Pearl Harbor during the attack was commissioned 

in 1923. Japan, on the other hand, had to build new ships to get to its limit 

and also had no plans to reinforce its bases in the Mandated Islands. Concurrently, the treaty prevented Britain and the United States from building 

fortresses in Japan’s “backyard.” Ultimately, the only type of ship that all 

three nations possessed fewer of than the treaty allowed was aircraft carriers. By 1937 both the United States and Japan were working hard to build 

new aircraft carriers.

In the late 1920s and early 1930s, Japan suffered from the international 

economic depression. The depression decimated Japan’s economy, and the 

resulting unemployment bolstered the Japanese military’s desire to seize 

parts of China to acquire much-needed natural resources. In September 

1931 Japan initiated a war against China. Asserting that China had planned 

to blow up a Japanese railroad, Japan attacked Chinese troops in Manchuria. By February 1932 Japan had seized Manchuria, renamed it Manchukuo, installed a “puppet” government, and turned it into a Japanese colony. 

When the League of Nations protested, Japan simply withdrew from the 

league, which was one of the first steps in the league’s ultimate demise.

Japan’s desire to expand its empire led to the “China incident,” a clash 

with Chinese troops near the Marco Polo Bridge on 7 July 1937. For the 

next six months, Japanese troops attacked to the west and south against 

ineffective Chinese resistance and were able to capture large expanses 

of territory. Logistics problems and Chinese guerrilla warfare caused the 

advance to slow but not before Japan had control of a vast amount of 

territory, including the capitol, Nanking. During the Japanese assault on 

Nanking, the USS Panay, a gunboat, was attacked by Japanese dive bombers and sunk. The attack outraged Americans, and the situation was only 

settled by a formal Japanese apology and payment of reparations.
50 

Throughout 1938 Japan continued its assault on China by consolidating gains, fighting guerrillas in newly captured areas, and continuing to 

drive west. In October the Japanese seized the port town of Canton, which 

gave them control of all of China’s main ports. Japan spent 1939 attempting to cut off all supply to the Chinese by capturing all of its remaining 

ports and concentrating on controlling the areas it occupied. Only the 

strong will of the Chinese people prevented China’s total collapse.

In June 1940 Japan demanded of the French Vichy government permission to land forces in French Indochina. Unable to confront Japan 

anyway, the Vichy government accepted the demand. The United States, 

in turn, warned Japan to stay out of French Indochina, but in September 

Japanese troops started landing and occupying northern parts of French 

Indochina, quickly occupying and using the airfields and ports. President 

Franklin D. Roosevelt’s administration reacted by placing an embargo on 

steel and scrap iron from the United States, an event the Japanese termed 

an “unfriendly act.”

The United States wanted Japanese expansion to stop and took severe actions to show its intentions. Congress passed a bill that called for 

increasing the size of the Navy by 300 percent by 1944. The US Pacific 

Fleet, home ported in San Diego, was on maneuvers in the Hawaiian Islands in May 1940, and at the end of the maneuvers, President Roosevelt 

ordered the fleet to remain at Pearl Harbor as a deterrent to the Japanese. 

Pacific Fleet Commander Admiral James O. Richardson protested against 

the move because he was concerned about Pearl Harbor’s ability to support the fleet logistically. Richardson protested so vehemently that he 

was relieved and replaced by Admiral Husband E. Kimmel in February 

1941.

Kimmel was concerned about not having enough ships to fight the 

Japanese if a war came, and instead of gaining ships, he lost 25 percent of 

his fleet. The president and secretary of the Navy decided that the Atlantic 

Fleet needed to be reinforced because they considered the endeavor to 

keep the sea line of communication to England open as the main effort. 

The Atlantic Fleet had to take up part of the escort duty, and to do so, 

it needed to be reinforced. Kimmel, who had requested reinforcement, 

instead was ordered to send the aircraft carrier Yorktown; the battleships 

Mississippi, Idaho, and New Mexico; four light cruisers; 17 destroyers; 

and 16 supply and auxiliary ships to the Atlantic.

On 27 September 1940 Japan allied itself with Germany and Italy by 

signing the Tripartite Treaty in Berlin where each side promised to aid the 
51

others for 10 years, but the treaty did not require Japan to declare war on 

Britain (who was at war with Germany and Italy).

In July 1941 Japan demanded more Indochinese bases and territory 

from the Vichy government, and when Japan moved to occupy these bases, the United States and its allies reacted swiftly and harshly. The United 

States, Great Britain, and the Netherlands froze Japanese assets, but more 

consequential to the Japanese, they imposed an all-out embargo against 

Japan, including the export of oil. Japan imported all of the oil it used and 

had now lost access to almost all of its sources. War in the Pacific grew 

closer.

Admiral Isoroku Yamamoto assumed duties as commander in chief of 

Japan’s Combined Fleet in August 1939. Yamamoto was not a pilot himself, but he had learned to appreciate the value of naval aviation and had 

held important naval aviation commands, including duty at the Navy flight 

school, chief of naval aviation, and command of an aircraft carrier division. Additionally, he held other key assignments, including an extended 

period of study at Harvard University followed by attaché duty at the US 

Embassy, duty as a representative at the London Naval Conference, and 

a tour as the vice minister of the navy. Yamamoto desperately wanted to 

avoid a war with the United States, but he also wanted to be prepared if 

war became inevitable or if he was ordered to wage war. Yamamoto’s experience taught him the United States’ industrial and technological advantage would make a prolonged war between the nations a losing struggle 

for Japan. He therefore determined that Japan would have to cripple the 

United States early in the fight so Japanese expansion could prosper to 

such a degree that the United States would have to sue for peace. He determined that Japan had to have free reign in the Pacific for six months to 

achieve a chance at victory. He also thought that naval aviation was the 

tool to crippling the Americans by destroying the US Pacific Fleet. His 

plan would become known as Operation HAWAII.

As early as March 1940, Yamamoto first considered an aerial strike 

on the US Pacific Fleet, and his thoughts quickly concentrated on Pearl 

Harbor when the Pacific Fleet moved there in May. Yamamoto first publicly declared his plan in January 1941 when he sent a letter to Navy 

Minister Admiral Koshiro Oikawa stating that war with the United States 

had become inevitable and that Japan should “attack and destroy the U.S. 

main fleet at the outset of the war” and that the attack should be at Pearl 

Harbor.

Yamamoto did not wait for permission from the Navy Ministry but 
52 

began gathering the best aviation and naval minds he could to plan the 

attack. He asked Rear Admiral Takijiro Onishi, Chief of Staff, 11th Air 

Fleet and a trusted friend, to study the idea. Onishi knew he needed an 

experienced pilot and planner who was smart, innovative, and fearless so 

he sent for Commander Minoru Genda, then serving as an air staff officer 

on the aircraft carrier Kaga. Genda was known throughout the Japanese 

navy as an exceptional aviator and planner, but his writings and arguments about employing air power were radical and alienated him from the 

“mainline” navy. That made Genda the perfect planner that Onishi needed. 

Onishi briefed Genda on Yamamoto’s concept and asked him to study the 

feasibility and to draft a report. Genda studied the concept for 10 days and 

determined the plan was feasible, given nine conditions:

1. The attack had to be a complete surprise.

2. The main objective should be the US aircraft carriers.

3. US land-based aircraft had to be destroyed to gain air superiority.

4. Every available Japanese aircraft carrier should participate.

5. All types of aircraft (torpedo, dive, high-level, fighter) should be 

used.

6. Fighters had to play an active role.

7. The attack had to be a daylight attack.

8. Japanese ships had to refuel at sea.

9. Attack planning had to be done in strict secrecy.

Yamamoto took Genda’s proposal, presented it to his staff, and started 

it working on gathering information on numerous subjects such as logistics, weather, method of attack, etc. Yamamoto still did not have permission to conduct this planning, but he thought if war came, an attack on 

Pearl Harbor was the only hope for Japan to have a chance for victory.

Genda’s idea of combining the carriers into one organization had been 

debated throughout the navy for a few years. Opponents of the concept 

were afraid the concentrated carriers, if located by the enemy, would 

make an easy target. Proponents believed concentrated carriers allowed 

for concentrating aircraft for strikes on the enemy, and having the carriers 

together allowed escorts to mass their abilities to protect the carriers from 

all enemies—air, surface, and submarine. Yamamoto was in favor of creating the First Air Fleet, and in the end he won out. On 10 April 1941 the 

Japanese navy created the First Air Fleet by combining the First Carrier 

Division (two carriers), the Second Carrier Division (two carriers), and 

the Fourth Carrier Division (one carrier). Now Japan had a command that 

ensured Yamamoto could easily concentrate the power of his air arm for 

operations. The pieces of Genda’s plan were beginning to fall into place.
53

Japan had taken the radical step of creating an aircraft carrier fleet but 

soon blundered when it named Vice Admiral Chuichi Nagumo to command it. The revolutionary carrier fleet needed an innovative thinker and 

commander, but Nagumo was a conservative, traditional naval officer. He 

had spent an accomplished career as a surface officer commanding cruisers, battleships, and surface ship divisions, but he had never even served in 

an aviation assignment. It was now his mission to lead the fleet that would 

start the war and hopefully set the conditions for victory for Japan.

Nagumo needed a competent staff to help him run his carrier fleet, so 

most of the exceptional staff officers from the carrier divisions were selected to serve Nagumo. Rear Admiral Ryunosuke Kusaka, an officer with 

experience commanding two aircraft carriers, was selected as the chief 

of staff. Perhaps the most important selection was Genda, who joined the 

First Air Fleet staff as air officer.

Once the First Air Fleet was a reality, training became the priority. The 

fleet’s ships maneuvered as they learned to work together as a fleet, while 

the aircraft on the carriers trained to conduct attacks against all kinds of 

targets under all kinds of conditions. The fleet staff worked to solve the 

problems determined in Genda’s nine-point concept. To use all types of 

aircraft for the attack, fleet staff officers had to determine a technique to use 

to incorporate the torpedo bombers (military thought of the day deemed 

Pearl Harbor too shallow for torpedo bombers), and they had to develop a 

bomb for the high-level bombers that would penetrate a battleship’s thick 

upper deck. Genda was the point man for each of these concerns.

Pearl Harbor was a very shallow port (approximately 40 feet), and 

Japanese torpedoes, using the current doctrine and equipment, would 

plunge to the bottom and get mired in the mud. Conventional wisdom said 

that the problem was insurmountable, but Genda believed the problem 

could be overcome. He gathered all of the best torpedo plane pilots from 

the fleet and told them they had to figure out how to employ or modify 

aerial torpedoes so they did not descend below 33 feet of water. Genda did 

not tell the pilots why, just that they had to solve the problem. The torpedo 

plane pilots worked frantically and tried all kinds of ideas before they 

came up with an acceptable solution. Japanese torpedo planes would fly at 

30 to 60 feet altitude (normal attack altitude was 300 feet) at a very slow 

speed. Additionally, the torpedoes were modified with a large wooden fin 

on the tail that would break off when the torpedo hit the water but not 

before reducing the depth of the torpedo’s plunge. Once the problem was 

resolved, Genda assigned the four best “Kate” squadrons to torpedo duty 

because he believed this would be the most difficult type of attack. The 
54 

selected crews began an intensive training regimen using the new techniques, still not knowing why.

The high-level bombers caused more of a problem for Genda than the 

torpedo bombers. Battleships had a thickly armored deck, and numerous 

large projectiles were needed to destroy a battleship. The Japanese did not 

have a bomb that could accomplish this. Additionally, the flyers’ bombing 

accuracy was very poor. Many planners would have given up, but Genda 

was a determined man. He once again assembled the best high-level pilots, and they worked together to solve the dilemma. They made many 

attempts, and after numerous failures solved the problem by converting 

16-inch battleship shells into bombs weighing 800 kilograms (1,700 lb). 

They discovered that if the bombs were dropped from 11,000 feet, they 

would penetrate a battleship’s deck. To solve the accuracy problem, the 

high-level bomber leaders implemented three initiatives to improve accuracy. First, they changed from a nine-ship triangle formation to a five-ship 

triangle formation. Second, every plane in the five-plane group would drop 

its bomb when the lead plane dropped its. Finally, the best bombardiers 

were teamed with the best high-level pilots. These hand-picked crews 

were selected to lead each five-ship formation. The crews also started an 

intense training routine, which combined with the three initiatives, drastically improved the high-level bombers’ accuracy.

The Japanese continued to incorporate Genda’s nine points into the 

plan, but all would be for naught if the First Air Fleet could not figure out 

how to refuel the ships at sea. For security, the First Air Fleet would travel 

a little-used northern route to Hawaii, which would preclude any possibility of refueling at a naval base. The older Japanese carriers had very limited ranges because of the belief that they would fight near Japanese home 

waters, and some of the smaller ships had small fuel tanks that limited 

their range. To make the attack, the Japanese would have to master the art 

of refueling at sea. Genda solved this problem using the technique he used 

solving other problems—he gathered the best tanker ship captains and told 

them to solve the problem.

The captains realized that the techniques in place (the tanker traveled 

in front of the ship to be refueled, floated a hose back to it, and refueled 

the ship) were sound for smaller ships (destroyers and cruisers), but lack 

of training was the stumbling block. Battleships and aircraft carriers were 

too big and not maneuverable enough to do this, so the tanker captains 

learned to follow the big ships and pass the hoses forward. The tankers 

first rehearsed the procedures with their own ships until they were proficient; then they began training with the First Air Fleet ships. Three refuel-
55

ing exercises were conducted in November, and all of the ships rehearsed 

refueling as the fleet concentrated before departing for Hawaii. Another 

obstacle that Genda identified had been overcome by innovative thinkers 

and training.

Throughout summer 1941 the First Air Fleet continued a vigorous 

training program with aircrews flying numerous missions at Ariake Bay on 

Kyushu, the southern most of Japan’s four main islands, which remarkably 

resembled Pearl Harbor. The ships continued maneuvering together, learning to sail and operate as a fleet while the tankers rehearsed their critical 

operations. The staff continued to refine the plan based on updated intelligence (covered in detail at the first stand) and changing circumstances.

In August Japanese war planning increased as the military leaders 

realized that war with the United States was more likely everyday. In response to the American embargo, the Imperial Staff developed the “Southern Operation,” a plan for capturing the industrial rich Dutch East Indies 

and Malaya. Japan realized this action would force the United States and 

Great Britain into war, so the plan also called for seizing the Americanheld Philippines and Guam and the British possessions of Hong Kong 

and Burma. Once the southern areas were secured, Japan would occupy 

strategic positions in the Pacific and fortify them, thus forming a tough 

defensive perimeter around Japan and its newly acquired resource areas. 

Once the perimeter was secure, Japan would try to negotiate for peace. 

The planners thought it would take six months to accomplish all the tasks 

and had to be free of interference from the American Navy during that 

time. Yamamoto had the plan for ensuring that the US Pacific Fleet would 

not interfere for six months.

On 6 August 1941 Yamamoto decided the time was right to brief the 

naval general staff on the Pearl Harbor attack plan. The naval general staff 

was considering moving the annual naval exercises from late November 

to September, and Yamamoto thought the exercise would be a great opportunity to rehearse the Pearl Harbor attack with exercise umpires, which 

would allow for a general after-action review of the plan. The naval general staff was unenthusiastic about the plan, considering it a gamble with 

the possible loss of most of Japan’s aircraft carriers as a real possibility. 

Despite its concerns, the staff accepted Yamamoto’s plan for further review.

At the end of August and the beginning of September, events occurred 

that would have enormous benefits for the Pearl Harbor plan. On 24 August Commander Mitsuo Fuchida was assigned to the First Air Fleet as 
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Figure 53.
57

commander of the air group responsible for leading the aircrews throughout training and would be the onsite commander during the actual raid. 

Fuchida had been Genda’s classmate at the military academy, and the two 

had remained friends ever since. Fuchida was known as one of the best 

high-level bomber pilots in the Japanese navy, but his leadership was the 

key to him being selected to command. Fuchida was an outstanding combat leader, levelheaded and cool in critical situations, but he was selected 

to command because he was able to convey the detailed plans from the 

staff into maneuvers that the energetic aircrews could execute. Fuchida 

was told what tasks the aircrews needed to be able to accomplish without 

being told of the plan. It was not until late September that Genda briefed 

Fuchida on the details of the plan.

In early September the Imperial General Staff briefed the emperor 

on war preparations, usually a formality because the emperor listened at 

these meetings and never said a word. However, Hirohito spoke up at this 

meeting, warning his military officers not to forgo negotiations as a way 

to avoid war. He emphasized that the Foreign Ministry would continue to 

negotiate with the United States and its Allies to try to solve the disagreement peacefully, and that the military should not do anything to hamper 

the discussions.

By late September two new aircraft carriers, composing the 5th Carrier Division, joined the First Air Fleet. Shokaku was completed on 7 August, and Zuikaku joined the fleet on 24 September. Their air wings had 

been formed before the ships were completed and had been training, and 

they now joined their ships. The 4th Carrier Division was transferred to 

other fleets, and the 5th Carrier Division was added to the First Air Fleet, 

meaning that Operation HAWAII now had six first-line aircraft carriers.

While the First Air Fleet continued to work on the air attack of Pearl 

Harbor, Yamamoto added another method of attack to the operation—submarines. In the end, 27 of Japan’s 63 submarines would take part in Operation HAWAII. Yamamoto wanted the submarines to participate to accomplish four tasks:

• Reconnaissance.

• Attacking ships leaving Pearl Harbor during and after the air attack.

• Protecting the First Air Fleet from any US surface fleet.

• Picking up downed flyers that could not make it back to the carriers.
58 

Additionally, the 6th Fleet (the submarine fleet) was tasked to create a 

Special Attack Force, five submarines that would carry midget submarines 

to Pearl Harbor. Japan had used midget submarines before, but these were 

launched from surface ships. The Japanese modified fleet submarines to 

carry the midget submarines to within 10 miles of Pearl Harbor where they 

would be launched to enter the harbor and attack American warships. The 

midget submarines were 78 feet long, weighed 46 tons, were armed with 

two torpedoes, had a crew of two, and had a range of 80 miles surfaced 

and 18 submerged. The air planners were distressed by the addition of submarines to their plans. They thought the chance of one of the submarines 

being spotted was excessive and would cause the entire raid to lose the 

element of surprise, deemed key by the air planners. Yamamoto listened 

to his airmen, but in the end he decided to maintain the submarines as part 

of the operation.

From 11 to 15 September the leaders of the Japanese navy gathered 

at the Naval Staff College to participate in the annual naval exercise, a 

command post exercise conducted in the buildings of the college. In a 

closely guarded secret room, Yamamoto gathered all of the officers who 

were aware of Operation HAWAII for a separate war game. From 11 to 14 

September Yamamoto participated in the exercise based on the Southern 

Operation. The different fleets conducted the operations they had been 

tasked to accomplish during the Southern Operation. For the most part, 

the exercise determined that that part of the plan was sound; only minor 

modifications were made.

On 15 September Yamamoto, closely watched by the representatives 

of the naval general staff, exercised Operation HAWAII. After discussions 

(some times heated) about which route to sail, the fleet, and preattack 

aerial reconnaissance, the exercise began. In the first iteration American 

reconnaissance aircraft located the Japanese fleet, resulting in the aircrews 

having to fight their way to the target and only causing minor damage 

to the US fleet. American bombers followed the Japanese planes back to 

their carriers where they sank two Japanese carriers and damaged two. A 

review of the action determined that the fleet had sailed too far south and 

had arrived at the launch point too early. The planners modified their plan 

and conducted another iteration in which the Americans did not spot the 

Japanese until the planes were over their targets. The Japanese destroyed 

two American carriers, four battleships, and three cruisers and damaged 

one carrier, one battleship, and three cruisers. Additionally, most of the 

American aircraft were destroyed. However, the few remaining American 

aircraft were able to locate the fleet and sink a Japanese carrier, a fact not 
59

lost on Nagumo who determined a quick escape from the area was key to 

his operations.

The day after the exercise, the participants gathered to discuss the 

exercise. The “American” and Japanese commanders briefed, as did the 

umpires. All agreed that the fleet had to sail a northerly route to avoid 

detection. They determined they had to arrive 450 miles from Hawaii at 

sunset because all American scout planes would be returning to base at 

that time, thus allowing the fleet to sail to the launch point undetected. 

Satisfied with the exercise, Yamamoto gathered the participants for a dinner that night, but he still did not have the naval general staff’s permission 

to conduct Operation HAWAII.

The Foreign Ministry continued negotiations with the United States, 

but it was really an exercise in futility. The United States demanded that 

Japan leave French Indochina and China before trade resumed, while 

the Japanese demanded the resumption of trade as the catalyst for other 

agreements. The two sides were irreversibly divided, but negotiations 

continued. As dialogue with the Americans faltered, the cabinet ministry 

contrived to get Japan on a wartime footing. On 15 October the prime 

minister and all of his cabinet resigned to allow the country to form a new 

“war” government. Hirohito, on the advice of his advisers, selected exWar Minister Hideki Tojo, an active duty army general, as the new prime 

minister. Tojo formed a cabinet with members he could control and also 

assumed the duties of war minister and army chief of staff. Japan now had 

a de facto military dictator, and any hope of a peaceful solution was over.

For the next month, the First Air Fleet refined its procedures while 

the naval general staff debated the merits of Operation HAWAII. Some 

on the staff considered the plan a gamble: how could six aircraft carriers 

sneak across the Pacific Ocean and attack the major US base without being 

detected? Others thought the assets earmarked for Hawaii could be better 

used in the Southern Operation. After all the Southern Operation was the 

main effort, and Operation HAWAII was a secondary effort. Yamamoto 

was convinced that the operation was imperative if Japan hoped to win 

any war with the United States. Therefore, on 17 October he sent one of 

his most trusted staff officers, Captain Kameto Kuroshima, to Tokyo to get 

a decision from the naval general staff. Kuroshima was no stranger to the 

naval general staff, having been dispatched by Yamamoto numerous times 

to brief it. Kuroshima briefed the merits of the plan one more time, but 

with each point he made, the staff responded by criticizing the plan.

Finally, Kuroshima played the trump card Yamamoto gave him. 
60 

Kuroshima informed the naval general staff that if Operation HAWAII

was not approved, Yamamoto could no longer guarantee Japan’s security, 

and he, therefore, would be compelled to resign. The staff officers could 

not believe their ears, but they did not want to risk losing the best admiral 

in the navy. They therefore approved the plan’s implementation if Japan 

went to war, as long as Yamamoto promised to make the carriers available 

to the Southern Operation as soon as possible after the attack. Yamamoto 

and his staff had meticulously planned for nine months, and now they had 

permission to conduct their operation, convinced that it was Japan’s best 

hope for defeating America.

During early November Japanese preparations accelerated as war 

became certain. Fuchida and the air planners completed their plan based 

on the war games. On 2 November Nagumo briefed all of the senior commanders (ship captains and carrier air group commanders) on the plan 

to attack the US fleet in Pearl Harbor. The First Air Fleet conducted full 

rehearsals of the attack on 3 to 6 November, with full after-action reviews 

and modifications to the plan based on events. Also on 6 November the 

Combined Fleet published Combined Fleet Order #1, which explained 

the entire plan (the Southern Operation and Operation HAWAII) from the 

initial attacks until the defensive perimeter was established. Events continued to transpire quickly.

The submarines began departing Japan on 11 November when the 3d 

Squadron sailed and was followed on 16 and 18 November by additional 

squadrons of submarines. All submarines proceeded to Japanese anchorages en route to refuel and were in position around Hawaii by 6 December. Throughout November, ships assigned to Operation HAWAII slowly 

slipped away from their home ports for the assembly point of Hitokappu 

Bay in the Kuril Islands. The Japanese intended to assemble the fleet in an 

isolated anchorage without drawing attention. By 22 November the fleet 

was assembled, and Nagumo briefed the operation to all of the subordinate 

commanders. He and his staff detailed the route they would sail, the plan 

of attack, contingencies if the fleet was spotted, logistics, etc. Yamamoto 

sent instructions to Nagumo on 24 November informing him that the fleet 

would sail the next day. The First Air Fleet, now renamed the Pearl Harbor 

Attack Force, lifted anchor and set sail on 25 November. Nagumo still did 

not have his attack orders; the diplomats were still trying. Nagumo would 

receive the attack order en route if negotiations failed.

The 30 ships of the Pearl Harbor Attack Force formed up and headed 

east led by the cruiser Abukuma, followed by four destroyers, the battleships 
61 Figure 54.
62

Hiei and Kirishima, which led the six carriers flanked by destroyers. The 

cruisers Tone and Chikuma flanked the formation while three submarines 

brought up the rear, ready to move forward to scout ahead. As the fleet 

steamed toward Pearl Harbor, the destroyers had to refuel everyday in 

the stormy seas of the northern route, losing sailors overboard during one 

operation.

On 1 December the cabinet met with the emperor in the Imperial 

Palace, and the decision was made that Japan had to declare war on the 

United States, Great Britain, and the Netherlands. The naval general staff 

informed Yamamoto, and on 2 December he gave a warning order to all 

of his subordinate fleet commanders telling them the exact date and time 

of their attacks would be sent on a later date. On 2 December Yamamoto 

received a message from the naval general staff, “Climb Mount Niitaka 

1208.” The coded message meant the war would begin on 8 December (7 

December Hawaiian time). Diplomacy had failed and Japan would attack 

the United States, Great Britain, and the Netherlands.

On 4 December the three tankers of Supply Group 2 refueled the task 

force and left formation to a linkup point where they would rendezvous 

with the task force during its return. On 6 December the four tankers of 

Supply Group 1 refueled all of the ships, and they too broke off to rendezvous with the fleet during its withdrawal. While the ships of the Pearl Harbor Attack Force refueled for the last time before the attack, Tojo cabled 

his ambassador to the United States, retired Admiral Kichisaburo Nomura, 

and informed him to be prepared to receive a 14-part message that had to 

be delivered to the United States before 0800, 7 December.

Once the tankers had departed, Nagumo raised the flag signal that 

Admiral Togo had raised before the Battle of Tsushima Straights: “The 

rise and fall of the Empire depends upon this battle: everyone will do 

his duty with utmost effort.” The fleet, now unencumbered by the slow 

tankers, increased speed to 24 knots to race to the launch point. The last 

day of peace the United States would enjoy for the next 31⁄2 years was 6 

December 1941.
63

III. Suggested Route and Vignettes

Introduction

The attack on Pearl Harbor occurred over two hours on 7 December 

1941. The Japanese attacked six major military installations all across 

Oahu that morning, leaving death and destruction in their wake. This 

guide is designed to examine the entire attack during a one-day visit. To 

accomplish this, an early start is required. Only two of the six major installations attacked that morning will be visited on this staff ride; the other 

four will be discussed at other locations.

The first couple of stands will discuss the antagonists’ preparations, 

and the last stands discuss the repercussions of the United States’ failings 

and Japan’s successes. The route of this guide follows no “tour” signs; 

therefore, the staff ride leader should recon the route before the staff ride 

and should have a detailed road map. Most of the stands are on active military installations, so be careful not to stray into off-limits areas.

The staff group leader may want to start this staff ride at a location 

where he or she can discuss the overview of the attack (Part II of this 

guide). Locations for this stand may be the Aiea Bay State Recreation Area 

picnic area (the first stand of the staff ride is in the same location but by the 

water looking at Pearl Harbor). This information may be covered the day 

or night before the ride in a briefing format.
65

Map to

Stands 4-7

H1 .

Porter

Gate

Pearl Harbor

W

Porter Ave

ater

Tower

Julian Ave

1st Street

Vickers Avenue Fort Kam Rd

Harbor D

S

r

eaman Ave

Note: This map is designed to assist you in finding stands.

Not all roads are shown. Obtain a base map to assist your navigation.

Flight Line

Stand 4

Stand 5

Stand 6

Stand 7

Hickam

Air Force Base

Boquet Blvd

Moo Atterbury Circle re St

H1 .

Porter

Gate

Pearl Harbor

W

Porter Ave

ater

Tower

Julian Ave

1st Street

Vickers Avenue Fort Kam Rd

Harbor D

S

r

eaman Ave

Note: This map is designed to assist you in finding stands.

Not all roads are shown. Obtain a base map to assist your navigation.

Flight Line

Stand 4

Stand 5

Stand 6

Stand 7

Hickam

Air Force Base

Boquet Blvd

Moo Atterbury Circle re St
66 

Map to

Stands 8-10

Saratoga Blvd

Stand 8

Stand 9

Stand 10

Ford Island Blvd

Ford

Island

Note: This map is designed to assist you in finding stands.

Not all roads are shown. Obtain a base map to assist your navigation.

Saratoga Blvd

Stand 8

Stand 9

Stand 10

Ford Island Blvd

Ford

Island

Note: This map is designed to assist you in finding stands.

Not all roads are shown. Obtain a base map to assist your navigation.
67

Stand 1

Japanese Espionage

Directions: The first stand is conducted at Aiea Bay State Recreation 

Area. From Kamehameha Highway (State Route 99) turn onto McGrew 

Loop. Make an immediate left at the “Aiea Bay State Recreation Area” 

sign. Park in the parking lot. If you plan to conduct an overview, move to 

the vicinity of the picnic area. When the overview is complete, move to the 

edge of the water where you can see Pearl Harbor.

Orientation: You are standing in the Aiea State Recreation Area. Today, any person can stand here and observe the activities in Pearl Harbor 

just as the Japanese spies did in 1941. The East Loch is the water to your 

front, the location where the destroyers berthed. Ford Island is directly 

across the loch, and the battleship is the USS Missouri, which is moored 

just fore of the USS Arizona on Battleship Row. The northwest side of 

Ford Island is where the aircraft carriers usually berthed.

Description: If the Japanese had any hope of crippling the US Pacific 

Fleet, they had to have extremely accurate intelligence on the ships of 

the fleet, the anchorage, and the other bases on Oahu that could influence 

any attack. Hawaii had a large Japanese population, both US citizens of 

Japanese descent and expatriates, who had always been a security concern 

for the United States. The Japanese government maintained a consulate 

7 miles from Pearl Harbor (it is still there) and had been using consulate 

personnel to observe US military activity for some time. When the Pacific 

Fleet transferred to Pearl Harbor in 1940, the Japanese government told 

Consul General Kiichi Gunji to send periodic reports on naval activity 

in Hawaii. Gunji selected the consulate’s treasurer, Kohichi Seki, to accomplish the task because he had attended the Naval Academy at Eta Jima 

before being discharged for medical reasons. The Honolulu newspapers 

published the schedule of fleet movements, and Seki simply rode a cab 

around Pearl Harbor to verify the newspaper accounts. As Seki continued 

his observations, he realized that the Pacific Fleet was extremely predictable; part of the fleet would depart on Monday and be back in port on 

Friday or Saturday. The Pacific Fleet was usually in port on Sundays.

As planning for Operation HAWAII progressed, the Japanese Consulate received a new employee, Tadashi Morimura, to assist with processing 

dual-nationality citizens. In fact, Morimura was actually Takeo Yoshikawa, a trained intelligence agent of the naval general staff. Yoshikawa 

was a graduate of Eta Jima who had been discharged from the Navy because of illness. He had extensive knowledge of the US Navy, and upon 
68 

his discharge, the naval general staff’s intelligence division sent him to 

school to improve his English, and trained him on the US Pacific Fleet. 

Yoshikawa arrived in Honolulu on 27 March 1941 and was immediately 

assigned one of the consulate’s bungalows and a car with driver, actions 

that seemed odd to the other members of the consulate staff.

Yoshikawa started his reconnaissance soon after his arrival. He selected several locations where he could observe Pearl Harbor, including Aiea. 

He soon confirmed the previous observation that the Pacific Fleet was usually in port on Sundays. As he became comfortable with his operations at 

Pearl Harbor, Yoshikawa began observing the other military installations 

on Oahu. He knew of the Naval Air Station (NAS) at Kaneohe, but he 

could not get close enough from the road to make accurate observations. 

He therefore decided to rent a boat, and using maids from the consulate 

as cover, anchored his “party” boat off the coast at Kaneohe and observed 

from there. When he had difficulty viewing Wheeler Field, he attended the 

Wheeler Field Open House on 6 August and was allowed to freely roam 

around the field. The only restriction was against taking pictures.

The airfields were the most difficult locations to observe, but the 

Japanese needed accurate information, so Yoshikawa continued to use 

the tourist cover. Taking one of the women employees of the consulate as 

his date, Yoshikawa rented an airplane and flew around all the different 

installations. Restrictions prevented him from overflying each installation, but observing the targets from the air allowed him to gather all the 

required information. At each airfield he was able to gather information 

on the runways, hangars, facilities, aircraft, and defenses. At Pearl Harbor 

he observed Ford Island NAS and the ships in anchorage. As Yoshikawa 

continued the routine of his espionage, he made another discovery that 

would be invaluable to attack planners. He noticed that US reconnaissance 

aircraft concentrated their searches south of Oahu. Yoshikawa was able to 

clearly view every major military installation and assess US forces’ exploitable patterns, and he forwarded that information to the naval general 

staff in Japan.

Based on Yoshikawa’s information, the naval general staff decided to 

recon the Pearl Harbor Attack Force’s planned sailing route. Normal shipping between Japan and the United States was suspended, but an agreement between the countries allowed limited sailings to repatriate citizens 

from one country to the other. On 23 October 1941 Tatuta Maru arrived 

in Honolulu with two intelligence agents aboard who carried instructions 

for the consulate and a supply of radios for civilian spies who were in 

place on Oahu in case the United States closed the consulate. The second 
69

ship, Taiyo Maru, arrived in Honolulu on 22 October, having sailed the 

exact route the attack force planned to use. The two intelligence agents 

aboard observed no other vessels on the route and learned that the US 

aerial screen line only extended 200 miles north of Oahu. The Taiyo Maru

arrived in harbor at 0830, the planned time of attack, so the agents could 

observe conditions on Oahu at the scheduled time of attack.

Before the attack, Japan had developed an extensive collection plan 

for all of the information required to precisely plan an attack on the Pacific Fleet. The planners knew about each of the airfields and the aircraft 

assigned to each, which allowed the planners to properly assign assets to 

each target. They knew the exact location where ships berthed so the planners could select appropriate routes with the appropriate assets to attack 

each target. In short, the Japanese had excellent intelligence from which 

to plan their attack.

Vignette: In 1943 the counterintelligence section of Fourteenth Naval 

District’s Intelligence Office published an analysis of espionage problems 

in Hawaii:

From the facts at hand, it must be said that almost all 

military and naval information known to have been 

transmitted from Hawaii to Japan, either by Consulate 

or agents sent here on special missions, was gathered by 

the simple expedient of open observation, without trespassing restricted areas. . . . In only a few instances were 

Consulate observers known to have used binoculars to 

observe Pearl Harbor and the Naval Air Station Kaneohe 

Bay, and even then, not illegally. . . . Accurate maps and 

charts of the Hawaiian Islands and adjacent waters long 

were on sale in downtown Honolulu, and available to any 

purchaser. Tourist maps showed the approximate location 

of many military and naval installations. Photographs of 

many strategic places on Oahu were on sale in Honolulu 

stores-even panoramic views of Pearl Harbor. . . . Unless vigorous, astute, and coordinated counter-espionage 

measures are placed in operation in Hawaii, the primary 

task of Counter-intelligence-denial of information to the 

enemy-will never be performed.

(Hearings Before the Joint Committee on the Investigation of the Pearl 

Harbor Attack, Congress of the United States, Seventy-Ninth Congress, 

Washington DC, 1946, part 35, 556-57, 572, hereafter cited as IPHA.)
70 

Teaching point 1. Counterespionage. In a free society, how can we 

prevent an enemy from conducting reconnaissance of a target if that enemy does not overtly break any laws?

As the staff ride leader leads this discussion, there are a few topics to 

consider. If a person is not breaking a law, you can not stop them. However, have the students consider:

a. If a person is a foreign national, reports of suspicious activity 

may lead to a professional counterespionage agency observing that person 

more closely.

b. There are steps we can take to make information gathering more 

difficult: watch what is posted on websites or is commercially available, 

understand where an installation is vulnerable to legal observation, and 

mitigate any possible damage from that location.

c. Altering defensive measures (shifting “Jersey barriers,” access 

points) makes reconnaissance less effective.

Teaching point 2. Predictability. Did the Pacific Fleet pattern of sailing 

on Mondays and returning on Saturdays give the enemy an edge?

The staff ride leader can have the students discuss US failures by developing a pattern that the enemy exploited (always being in port on Sunday, always focusing aerial screens to the south). Once the discussion lags, 

ask them, “How do you prevent predictability?” Issues here may include 

constant use of the same route, unchanged entrance procedures to a facility, lax and unaltered security procedures (like airport security screening 

before 11 September), etc.
71

Stand 2

Homeland Defense

Directions: Retrace your route back to Kamehameha Highway (State 

Route 99). Turn right on Kamehameha Highway (State Route 99) heading 

toward Pearl Harbor. Turn into the USS Arizona Memorial parking lot, 

and turn left at the bottom of the hill. Pull the vehicle as far south as you 

can (parking may be difficult here). Dismount and walk until you can observe the Kamehameha Highway bridge over Halawa Stream.

Orientation: In 1941 this bridge was designated the “New Kam Highway Bridge over Halawa Stream” in the Hawaiian Department’s standing 

operating procedures (SOP). It was one of 19 highway bridges the Hawaiian Department ordered to be guarded in the event of any alert. The 25th 

Infantry Division was responsible for this bridge and was guarding it on 7 

December 1941.

Description: In 1941, 37 percent of Hawaii’s population was Japanese; 

24 percent was Caucasian; 15 perecent was Hawaiian; and the remainder 

was mixed among Filipino, Chinese, Puerto Rican, and Korean. With such 

a large percentage of Japanese people living in Hawaii, the military was 

extremely concerned about sabotage. As such, it designated crucial civilian infrastructure for protection. In its SOP, the Hawaiian Department 

ordered numerous civilian facilities to be guarded during any alert. Those 

facilities included 51 railroad bridges, 19 highway bridges, five telephone 

exchanges, eight electric substations, one cold storage plant, four water 

pumping stations, and one radio station. Both the 24th and 25th Infantry 

Divisions developed their own SOPs that required their subordinate units 

to occupy defensive positions in case of attack by military forces and required protection for these critical locations (see figure 55).

When the Hawaiian National Guard was federalized in October 1940, 

the territorial governor was left with a void of military strength for his own 

use. Realizing it was his responsibility to guard the key facilities that the 

US Army was guarding, the governor passed a law creating the Hawaiian Territorial Home Guard, a militia organization that would replace the 

federalized National Guard. Unfortunately, the Hawaiian Territorial Home 

Guard had not been organized by 7 December 1941.

LTG Short was concerned about protecting the citizens of Oahu in 

case of attack. In March 1941 he published, in conjunction with local civilian governments, a plan to protect Oahu’s civilian population in case 

of bombardment. The extensive plan detailed how the city of Honolulu 
72 

and Oahu’s territorial government would protect its citizens in case of an 

attack. The plan included sections on organization, air raid protection, 

evacuation, and use of workers.

In the event of attack, Honolulu would use the police and fire departments to deal with the situation initially. Then, a “General Committee,” 

consisting of the mayor, a secretary, representatives of the Hawaiian 

Department and 14th Naval District, FBI, and chairmen of appointed subcommittees, would deal with the emergency. The subcommittees, headed 

by an appropriate official and with members from key organizations, 

would manage specific problems. The subcommittees follow.

Figure 55.
73

 Subcommittee Chairman Duties

Law Enforcement Chief of Police Patrolling

Prison camps

Traffic control

Blackout enforcement

Relief Red Cross Chairman Food rationing

Billeting

Medical aid

Casualty reporting

Damage Control City Chief Engineer Fire protection

Clear ruins

Construct defense works

Bury the dead

Procurement City & County Purchasing Agent Food preparation

Fuel maintenance

Purchase supplies

Finance City and County Comptroller Control expenditures

Emergency budget

preparation

Legislative City and County Attorney Prepare legislation

Special court establishment

Emergency labor laws

Public Relations Not mentioned Morale

 and Publicity Publicity

Public education

Additional civilian subcommittees (advisory groups) were also planned. 

These included housing, food, transportation, labor, publicity, engineering, medical, and damage control.

Civilian protection from air attack was a major concern, so the officials extensively planned to protect the citizens from the air. Hawaii was 

divided into districts and divisions that contained medical support, chemical protection, rescue teams, and collection stations. The plan detailed 

diagrams and descriptions of shelters civilians could construct and maps 

to large, government shelters. In case of attack, officials wanted to evacuate all nonessential personnel to reduce casualties. The plan had locations 

(with the number of personnel the facility could accommodate) and a comprehensive transportation plan.
74 

The planners realized extensive labor would be needed after an attack 

and planned to use 20,000 workers to assist in any recovery and in defensive preparation. The plan detailed “bed-down” locations for the workers 

and a general plan of requirements; detailed plans would be developed 

based on the situation. However, this effort ensured a ready pool of skilled 

workers prepared to provide any support that was needed.

Vignette: On 23 December 1941 Hawaii Governor J.W. Poindexter 

reflected on the plan to protect citizens in a letter to Hawaiian Department 

Commander LTG Walter Short: “The citizens of the Hawaiian Islands 

have always appreciated that these Islands were important to National 

Defense from a military standpoint, but it has been only since your arrival 

in these Islands on February 5, 1941 that it has been brought home to the 

civil population the importance of the part it would play in the event of a 

war in the Pacific. On December 7th, the citizens of these Islands met the 

hour of their test in such a manner as to make me proud to be the Chief 

Executive of these Islands. Your foresight in urging the population to prepare to meet the possible vicissitudes of war and the joint efforts of the 

Army and civil population in planning and preparing for this emergency 

was magnificently rewarded.” (IPHA, part 24, 1,932.)

Teaching point 1. Critical site defense. How extensively have we 

planned to defend civilian and military sites that are critical to military 

operations around our home bases?

The staff ride leader should get the students to discuss how prepared 

their units are to deal with an attack at their own installations. Before 

11 September this seemed impossible, but now posts and units must be 

prepared to defend themselves at home. Ask the students what the critical locations are on and around their posts or bases and about the plan to 

defend them.

Teaching point 2. Civil defense. How extensively have our cities 

planned for civil defense?

Honolulu had a meticulous plan for dealing with an attack, and on 7 

December, they were able to successfully respond to the Japanese attack. 

Fire units were quickly dispatched to fight fires and handle destruction, civilians were evacuated, work parties were quickly formed, and a blackout 

was quickly initiated and enforced, due largely to having a good plan on 

the shelf. Have the students discuss how well they think our citizens and 

towns are prepared for another attack. More important, have them discuss 

their responsibility for civil defense.
75

Stand 3

American Intelligence

Directions: Depart the USS Arizona Memorial parking lot and turn 

right on Kamehameha Highway (State Route 99). Enter Pearl Harbor 

Naval Base through the Makalapa Gate (security police will check your 

vehicle for Department of Defense stickers and check each person’s identification). Once through the gate, turn left on North Road. At the Nimitz 

Gate, North Road becomes South Avenue. From the Nimitz Gate, drive 

0.8 miles on South Avenue and turn right on Russell Avenue. Drive 0.4 

miles (go straight at the Stop sign) and park near the two-story building 

with long, exterior balconies on the right. Conduct the stand in the grass 

in front of the building.

Orientation: This is Building 1 at Pearl Harbor, the Naval Shipyard 

Administration Building. In 1941 the Combat Intelligence Unit (CIU), 

commanded by Commander Joseph Rochefort, was located in this building. Rochefort and CIU determined that Japan was going to attack Midway in 1942, which allowed the United States to ambush and win the 

decisive Battle of Midway. (Hal Holbrook played Rochefort in the 1976 

movie, “Midway.”) Ford Island is 300 meters to the north, and Hickam Air 

Force Base is to the south.

Description: The American authorities knew the Japanese were conducting espionage all over Oahu, but there was nothing they could do to 

stop it. The FBI, the Navy District Intelligence Office (DIO), Hawaiian 

Department G2, and the Honolulu police all had learned of the consulate 

activities and observed the Japanese as they gathered their information, 

but since the Japanese were not overtly breaking the law, they could not 

stop them. These counterintelligence professionals let the Japanese know 

they knew they were conducting espionage in an attempt to intimidate 

them, would talk to them as they departed the consulate grounds, and let 

them know they were following them.

The counterintelligence agencies were able to get some wiretaps on a 

few phones in the consulate, but they concentrated on the senior members 

who were not involved in spying, so they did not gain any intelligence 

from the taps. In hope of determining what information the Japanese were 

passing to Tokyo, the DIO attempted to get copies of the cables sent from 

the consulate, but the telegraph companies would not violate the Federal 

Communications Act of 1934 that prohibited intercepting messages to and 

from a foreign country. While the counterintelligence agencies were unable to stop Japanese intelligence gathering, other government agencies 
76 

were having success in determining Japan’s intentions; the United States 

was reading Japan’s diplomatic traffic.

The Japanese had developed a series of codes for their diplomats to 

use. The most secure and the one the Japanese most trusted was termed 

“Purple.” This was a system that used a combination of machinery and 

ciphers to secure message traffic and was so intricate that the Japanese 

were convinced that it could not be broken. The problem for the Japanese 

was that the United States had broken it in August 1940 and had been reading its most important diplomatic traffic ever since. The US Army Signal 

Intelligence Service hired the best cryptologists, spent 18 months working 

on the problem, and was eventually successful. The Japanese used other, 

less secure codes (mainly, the J-series codes) that the United States also 

broke. The information gathered from all of the diplomatic codes was 

called “Magic” intelligence. The US Army and Navy synergistically cooperated on Magic, with the Army concentrating on Purple while the Navy 

concentrated on the J series.

On the surface, Magic seemed like a great advantage for the United 

States, but it had many problems. Purple messages only contained information the foreign office wanted its diplomats to know, and often it was 

better if the diplomats in the United States did not know much. There were 

only eight Purple decrypting machines in existence, and the United States 

had to thoughtfully decide who should have them. In the end, four were 

placed in Washington (two for the Army, two for the Navy), three were 

provided to the British Allies, and the last was given to General Douglas 

MacArthur, commander, US Armed Forces Far East, in the Philippines. 

Hawaii did not have its own machine and depended on Washington for 

Magic information.

The Japanese sent an average of 26 messages a day using the Purple 

code, which caused difficulties for the US code breakers because it took up 

to a week to decode each message. Once decoded, the message had to go 

to another office to be translated, and due to an acute shortage of qualified 

Japanese linguists, it could take another week to translate any message. It 

could take up to 14 days before intelligence officers had the message in 

their hands.

The US intelligence experts had to decide carefully who could be 

exposed to Magic intelligence. If too many people knew of Magic information, the Japanese could determine that the Purple code was broken 

and they could change the code. Therefore, the Army only allowed the 

Secretary of War, the Chief of Staff, the Chief of War Plans, and the G2 to 
77

be exposed to “Magic.” The Navy only allowed access to the Secretary of 

the Navy, the Chief of Naval Operations (CNO), the Chief of War Plans, 

and the Chief of Intelligence. The president had access to Magic, but even 

this was stopped for a while when a copy of a Magic message was found in 

his military secretary’s trash. Each service issued general guidance to their 

subordinates based on Magic but were very careful to conceal the source, 

which sometimes led to very simple information being delivered to commanders when more detailed information was available.

While intelligence units in Washington were reading the diplomatic 

traffic, the CIU was reading the Japanese navy’s “flag officer’s” code, the 

most secure naval code that was used to pass critical naval communications. The CIU had cracked the code in 1926 and had been reading it ever 

since. Unfortunately, on 1 December 1940 the Japanese changed the flag 

officer’s code, and the CIU could not break the new code until after the 

United States was thrust into the war. The CIU would, however, break the 

code again, which provided information that was instrumental in the overwhelming American victory at Midway.

Despite being able to read many of the Japanese codes, the Navy’s 

senior leaders were affected by a power struggle between the Chief of 

War Plans and the Chief of Intelligence. Each organization wanted to produce the data on Japanese intentions based on intelligence gathered by all 

sources. This in-fighting produced nothing but mistrust and poor information for the Navy’s senior commanders.

Despite the troubles and tribulations of gaining Magic, the intercepts 

did provide the United States with some critical information. On 24 September 1941 (message not decoded and translated until 9 October) the 

Japanese sent detailed instructions on how to report the locations of ships 

in Pearl Harbor to the consulate in Honolulu using a detailed grid system 

(this is known as the “bomb plot” message). Army intelligence analysts 

considered the message significant, but senior leaders did not and never 

forwarded any information about it to LTG Short, the Hawaiian Department commander. Navy senior leaders considered the message interesting but not critical and ordered the information passed to the Pacific and 

Asiatic Fleets. For unknown reasons Admiral Kimmel never received the 

message, but Washington assumed he had.

On 15 November 1941 (message not decoded and translated until 3 

December) the Japanese consulate was ordered to make reports on Pearl 

Harbor twice a week and to alter the times they sent each report. Washington decided not to send this information to the commanders in Hawaii.
78 

On 29 November 1941 the Japanese Foreign Ministry sent a message 

to all if its embassies and consulates around the world with a series of 

code words that would be broadcast on Japanese open shortwave radio 

networks during the weather report indicating when diplomatic relations 

were going to be severed, a step just short of war. There were codes for 

severing relations with the USSR, England, and the United States. The 

code for cutting relations with the United States was “East Wind Rain,” so 

the message became known as the “winds message.” Again, this information was never passed to Kimmel and Short, nor were they informed when 

one of the codes was heard on 3 December.

On 6 December 1941 the code breakers intercepted a message to 

the Washington embassy telling them to be prepared to receive a 14-part 

message that had to be delivered to the US State Department by 1300, 7 

December (0800 Hawaiian time). When the message came in, the US code 

breakers were able to decrypt it and translate it faster than the Japanese 

embassy, and when Roosevelt read it, he supposedly said, “This means 

war.” (Popular lore says this message was a declaration of war. In fact, 

it was a reply to a previous message the United States sent. While the 

message “meant war,” it was not itself a declaration of war.) When Army 

Chief of Staff General George C. Marshall saw the message, he ordered 

war warnings to be sent to all commands. The Army Staff sent messages to 

all subordinate commanders, but atmospheric conditions prevented it from 

sending the message to the Hawaiian Department. The officer responsible 

for sending the message could have asked the Navy to send the message 

but instead decided to send it by civilian telegraph. The message arrived 

in Honolulu at 0733, 7 December and did not arrive at Fort Shafter (Hawaiian Department headquarters) until 1145. It was not decoded and into 

Short’s hands until 1458.

Vignette: The counterintelligence agents’ frustration is apparent in 

Rear Admiral Theodore S. Wilkinson’s testimony to the Hart Commission in 1944. Wilkinson, who was a commander and Director, Office of 

Naval Intelligence, in December 1941, testified: “It would also be indicated similarly elsewhere, but the fact that a comprehensive espionage 

was being carried on was, I think, known through the district intelligence 

officers to the naval commanders in all of these ports, and I know that the 

time I was in Hawaii, that we were cognizant of that fact, and we were 

helpless to stop it. We could not censor their mails. We could not censor 

the dispatches. We could not prevent the taking of photographs. We could 

not arrest Japanese suspects. There was nothing we could do to stop it, 

and all hands knew that espionage was going on all along, and reports 
79

were going back to Japan.” (IPHA, part 4, 1,841).

Teaching point 1. Freedom versus security. Do laws like the Federal 

Communications Act of 1934, which are passed to secure our freedom, in 

fact make the nation less safe?

The staff ride leader should get students to compare and contrast laws 

that secure our freedom and laws that limit freedoms but maintain security. 

As the discussion continues, inject the Patriot Act and ask students if the 

loss of certain civil liberties is worth the protection gained.

Teaching point 2. Language skills. How did a lack of skilled linguists 

affect the Americans’ ability to gather intelligence?

Due to this shortage, critical messages could take a week to translate. 

Ask students if our nation is better off today. (On 28 September 2004 the 

New York Times reported that 120,000 hours of potentially valuable terrorism-related recordings have not been translated due to a shortage of skilled 

linguists in the FBI.) Ask students how we can improve our language capability.

Teaching point 3. Dissemination. What good is having great intelligence if you cannot share it with the commanders who need it?

Have students discuss how to keep sources and methods secret while 

still being able to provide information to those who really need it. The 

staff ride leader can also discuss how certain staff officers in 1941 failed 

to ensure messages were received (Kimmel not receiving the bomb plot 

message and Short receiving Marshall’s war warning after the attack was 

over). Ask students if we are better at this today, or is it assumed that once 

we hit the “send” button, the action is complete?