Question: What was Isoroku Yamamoto's role in "the most stunning and decisive blow in the history of naval warfare."?

Context articles: Isoroku (film)
John Ashmead
Anti-surface warfare
Japanese naval codes
Isoroku Yamamoto's sleeping giant quote
Toshio Miyazaki
Operation Vengeance
Isoroku Yamamoto
Battle of Tsushima
Battle of Midway

Isoroku (Japanese: 聯合艦隊司令長官 山本五十六 – 太平洋戦争70年目の真実- , Hepburn: Rengō Kantai Shirei Chōkan: Yamamoto Isoroku – Taiheiyō Sensō Nanajūnenme no Shinjitsu– , "Combined fleet commander Yamamoto Isoroku – Truth of the Pacific War 70 years ago") is a 2011 Japanese war drama film about Isoroku Yamamoto.
John Ashmead (1917–1992) was an American novelist, Naval Intelligence officer, and professor of English.
 His writings include "The Mountain and the Feather" about his experiences in the Pacific in World War II as a United States naval intelligence officer and translator.
 He received a commendation for obtaining information that helped Navy fliers shoot down the plane of Japanese Admiral Isoroku Yamamoto, who had masterminded the 1941 surprise attack on the U.S. military base at Pearl Harbor, HI, which brought the United States into the fighting.
 He co-authored "The Songs of Robert Burns" in 1988 with Professor John Davison.
 His PhD thesis was "The Idea of Japan 1853-1895: Japan as Described by American and Other Travellers from the West".
 * Ashmead was a graduate of Navy Japanese language program at the University of Colorado, Boulder and Berkeley.
 His work as a translator for Naval Intelligence aided in the assassination of Admiral Isoroku Yamamoto.
 He was a professor of English at Haverford College from 1948 to 1988.
 At Haverford, he pioneered the use of computers in education and research.
 He spoke as Fulbright lecturer in Osaka and Kyoto, Japan, Taipei, Varanasi, India and throughout India, and also taught in Athens, Greece at Athens College for Boys.
Anti-surface warfare (ASuW or ASUW) is the branch of naval warfare concerned with the suppression of surface combatants.
 More generally, it is any weapons, sensors, or operations intended to attack or limit the effectiveness of an adversary's surface ships.
 Before the adoption of the submarine and naval aviation, all naval warfare consisted of anti-surface warfare.
 The distinct concept of an anti-surface warfare capability emerged after World War II, and literature on the subject as a distinct discipline is inherently dominated by the dynamics of the Cold War.
The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well.
 Every Japanese code was eventually broken, and the intelligence gathered made possible such operations as the victorious American ambush of the Japanese Navy at Midway (JN-25b) and the shooting down of Isoroku Yamamoto in Operation Vengeance.
Isoroku Yamamoto's sleeping giant quotation is a quote by the Japanese Admiral Isoroku Yamamoto regarding the 1941 attack on Pearl Harbor by forces of Imperial Japan.
Toshio Miyazaki (宮崎敏夫 , Miyazaki Toshio , extra-December 18, 1899 – April 4, 1965) was a career officer in the Imperial Japanese Navy.
 He gained notoriety in the United States after his arrest and subsequent deportation for espionage activities.
 A protégé of Admiral Isoroku Yamamoto, during the Pacific War his anticipated promotion to the senior staff of the Combined Fleet was not realized due to Yamamoto’s death, and he ended the war with the rank of captain.
Operation "Vengeance" was the American military operation to kill Admiral Isoroku Yamamoto of the Imperial Japanese Navy on April 18, 1943, during the Solomon Islands campaign in the Pacific Theater of World War II.
 Isoroku Yamamoto, commander of the Combined Fleet of the Imperial Japanese Navy, was killed on Bougainville Island when his transport bomber aircraft was shot down by United States Army Air Forces fighter aircraft operating from Kukum Field on Guadalcanal.
Isoroku Yamamoto (山本 五十六 , Yamamoto Isoroku , April 4, 1884 – April 18, 1943) was a Japanese Marshal Admiral of the Navy and the commander-in-chief of the Combined Fleet during World War II until his death.
The Battle of Tsushima (Russian: Цусимское сражение , "Tsusimskoye srazheniye"), also known as the Battle of Tsushima Strait and the Naval Battle of the Sea of Japan (Japanese: 日本海海戦, "Nihonkai-Kaisen") in Japan, was a major naval battle fought between Russia and Japan during the Russo-Japanese War.
 It was naval history's only decisive sea battle fought by modern steel battleship fleets, and the first naval battle in which wireless telegraphy (radio) played a critically important role.
 It has been characterized as the "dying echo of the old era – for the last time in the history of naval warfare, ships of the line of a beaten fleet surrendered on the high seas".
The Battle of Midway was a decisive naval battle in the Pacific Theater of World War II which occurred between 4 and 7 June 1942, only six months after Japan's attack on Pearl Harbor and one month after the Battle of the Coral Sea.
 The United States Navy under Admirals Chester Nimitz, Frank Jack Fletcher, and Raymond A. Spruance defeated an attacking fleet of the Imperial Japanese Navy under Admirals Isoroku Yamamoto, Chuichi Nagumo, and Nobutake Kondo near Midway Atoll, inflicting devastating damage on the Japanese fleet that proved irreparable.
 Military historian John Keegan called it "the most stunning and decisive blow in the history of naval warfare."