Battle of Saipan The Battle of Saipan was a battle of the Pacific campaign of World War II , fought on the island of Saipan in the Mariana Islands from 15 June – 9 July 1944 . The Allied invasion fleet embarking the expeditionary forces left Pearl Harbor on 5 June 1944 , the day before Operation Overlord in Europe was launched . The U . S . 2nd Marine Division , 4th Marine Division , and 27th Infantry Division , commanded by Lieutenant General Holland Smith , defeated the 43rd Division of the Imperial Japanese Army , commanded by Lieutenant General Yoshitsugu Saito . Background . In the campaigns of 1943 and the first half of 1944 , the Allies had captured the Solomon Islands , the Gilbert Islands , the Marshall Islands and the Papuan Peninsula of New Guinea . This left the Japanese holding the Philippines , the Caroline Islands , Palau Islands and Mariana Islands . It had always been the intention of the American planners to bypass the Carolines and Palaus and to seize the Marianas and Taiwan . From these latter bases communications between the Japanese homeland and Japanese forces to the south and west could be cut . In addition , from the Marianas Japan would be well within the range of an air offensive relying on the new B - 29 Superfortress long - range bomber with its operational radius of . While not part of the original American plan , Douglas MacArthur , commander of the Southwest Pacific Area command , obtained authorization to advance through New Guinea and Morotai toward the Philippines . This allowed MacArthur to keep his personal pledge , made in his " I shall return " speech , to liberate the Philippines , and also allowed the active use of the large forces built up in the southwest Pacific theatre . The Japanese , expecting an attack somewhere on their perimeter , thought an attack on the Caroline Islands most likely . To reinforce and supply their garrisons , they needed naval and air superiority , so Operation A - Go , a major carrier attack , was prepared for June 1944 . Battle . Bombardment of Saipan began on 13 June 1944 . Fifteen battleship s were involved , and 165 , 000 shells were fired . Seven modern fast battleships delivered twenty - four hundred shells , but to avoid potential minefields , fire was from a distance of or more , and crews were inexperienced in shore bombardment . The following day the eight pre - Pearl Harbor battleships and eleven cruisers under Admiral Jesse B . Oldendorf replaced the fast battleships but were lacking in time and ammunition . The landings began at 07 : 00 on 15 June 1944 . More than 300 LVT s landed 8 , 000 Marines on the west coast of Saipan by about 09 : 00 . Eleven fire support ships covered the Marine landings . The naval force consisted of the battleship s and . The cruiser s were and . The destroyer s were , , , , , and . Careful Japanese artillery preparation — placing flags in the lagoon to indicate the range — allowed them to destroy about 20 amphibious tanks , and the Japanese strategically placed barbed wire , artillery , machine gun emplacements , and trenches to maximize the American casualties . However , by nightfall the 2nd and 4th Marine Divisions had a beachhead about wide and deep . The Japanese counter - attacked at night but were repulsed with heavy losses . On 16 June , units of the U . S . Army ' s 27th Infantry Division landed and advanced on the airfield at Ås Lito ( which is now the location of Saipan International Airport ) . Again the Japanese counter - attacked at night . On 18 June , Saito abandoned the airfield . The invasion surprised the Japanese high command , which had been expecting an attack further south . Admiral Soemu Toyoda , commander - in - chief of the Japanese Navy , saw an opportunity to use the " A - Go " force to attack the U . S . Navy forces around Saipan . On 15 June , he gave the order to attack . But the resulting battle of the Philippine Sea was a disaster for the Imperial Japanese Navy , which lost three aircraft carriers and hundreds of planes . The garrisons of the Marianas would have no hope of resupply or reinforcement . Without resupply , the battle on Saipan was hopeless for the defenders , but the Japanese were determined to fight to the last man . Saito organized his troops into a line anchored on Mount Tapotchau in the defensible mountainous terrain of central Saipan . The nicknames given by the Americans to the features of the battle — " Hell ' s Pocket " , " Purple Heart Ridge " and " Death Valley " — indicate the severity of the fighting . The Japanese used the many caves in the volcanic landscape to delay the attackers , by hiding during the day and making sorties at night . The Americans gradually developed tactics for clearing the caves by using flamethrower teams supported by artillery and machine guns . The operation was marred by inter - service controversy when Marine General Holland Smith , unsatisfied with the performance of the 27th Division , relieved its commander , army Major General Ralph C . Smith . However , General Holland Smith had not inspected the terrain over which the 27th was to advance . Essentially it was a valley surrounded by hills and cliffs under Japanese control . The 27th took heavy casualties and eventually , under a plan developed by General Ralph Smith and implemented after his relief , had one battalion hold the area while two other battalions successfully flanked the Japanese . By 7 July , the Japanese had nowhere to retreat . Saito made plans for a final suicidal banzai charge . On the fate of the remaining civilians on the island , Saito said , " There is no longer any distinction between civilians and troops . It would be better for them to join in the attack with bamboo spears than be captured . " At dawn , with a group of 12 men carrying a great red flag in the lead , the remaining able - bodied troops — about 3 , 000 men — charged forward in the final attack . Amazingly , behind them came the wounded , with bandaged heads , crutches , and barely armed . The Japanese surged over the American front lines , engaging both army and marine units . The 1st and 2nd Battalions of the 105th Infantry Regiment was almost destroyed , losing 650 killed and wounded . However , the fierce resistance of these two battalions , as well as that of Headquarters Company , 105th Infantry , and supply elements of 3rd Battalion , 10th Marine Artillery Regiment resulted in over 4 , 300 Japanese killed . For their actions during the 15 - hour Japanese attack , three men of the 105th Infantry were awarded the Medal of Honor — all posthumously . Numerous others fought the Japanese until they were overwhelmed by the largest Japanese Banzai attack in the Pacific War . By 16 : 15 on 9 July , Admiral Turner announced that Saipan was officially secured . Saito — along with commanders Hirakushi and Igeta — committed suicide in a cave . Also committing suicide at the end of the battle was Vice - Admiral Chuichi Nagumo — the naval commander who led the Japanese carriers at Pearl Harbor and Midway — who had been assigned to Saipan to direct the Japanese naval air forces based there . In the end , almost the entire garrison of troops on the island — at least 30 , 000 — died . For the Americans , the victory was the most costly to date in the Pacific War . 2 , 949 Americans were killed and 10 , 464 wounded , out of 71 , 000 who landed . Hollywood actor Lee Marvin was among the many American wounded . He was serving with " I " Company , 24th Marine Regiment , when he was shot in the buttocks by Japanese machine gun fire during the assault on Mount Tapochau . He was awarded the Purple Heart and was given a medical discharge with the rank of Private First Class in 1945 . Civilian casualties . Saipan had been seized by Japan after World War I , and thus a large number of Japanese civilians lived there — at least 25 , 000 . The U . S . erected a civilian prisoner encampment on 23 June 1944 that soon had more than 1 , 000 inmates . Electric lights at the camp were conspicuously left on overnight to attract other civilians with the promise of three warm meals and no risk of accidentally being shot in combat . Weapons and the tactics of close quarter fighting also resulted in high civilian casualties . Civilian shelters were located virtually everywhere on the island , with very little difference noticeable to attacking marines . The standard method of clearing suspected bunkers was with high - explosive and / or high - explosives augmented with petroleum ( e . g . , gelignite , napalm , diesel fuel ) . In such conditions , high civilian casualties were inevitable . Emperor Hirohito personally found the threat of defection of Japanese civilians disturbing . Much of the community was of low caste , and there was a risk that live civilians would be surprised by generous U . S . treatment . Native Japanese sympathizers would hand the Americans a powerful propaganda weapon to subvert the " fighting spirit " of Japan in radio broadcasts . At the end of June , Hirohito sent out an imperial order encouraging the civilians of Saipan to commit suicide . The order authorized the commander of Saipan to promise civilians who died there an equal spiritual status in the afterlife with those of soldiers perishing in combat . General Hideki Tōjō intercepted the order on 30 June 1944 and delayed its sending , but it went out anyway the next day . By the time the marines advanced on the north tip of the island , from 8 – 12 July 1944 , most of the damage had been done . 1 , 000 Japanese civilians committed suicide in the last days of the battle to take the offered privileged place in the afterlife , some jumping from " Suicide Cliff " and " " Banzai " Cliff " . On 16 June 1944 Gunnery Sergeant Robert H . McCard , a Marine , killed sixteen enemies while sacrificing himself to ensure the safety of his tank crew . McCard was posthumously awarded the Medal of Honor for his actions . The , a " Gearing " - class destroyer , was named in his honor . On 25 June 1944 , PFC Harold G . Epperson , part of the 2nd Marine Division , threw himself on a grenade to contain the blast from killing members of his squad . For his bravery and sacrifice , PFC Epperson was posthumously awarded the Medal of Honor . Epperson ' s Medal of Honor was presented to his mother in a ceremony on Wednesday , 4 July 1945 in Tiger Stadium , Massillon , Ohio . The , a " Gearing " - class destroyer , was named in his honor . When his battalion came under attack from a much larger enemy force on 7 July , Lieutenant Colonel William O ' Brien refused to leave the front lines even after being wounded , and continued to lead his men until being overrun and killed . He was posthumously awarded the Medal of Honor on 9 May 1945 , for his actions throughout the battle for Saipan . The U . S . Army ship USAT " Col . William J . O ' Brien " , which served in the Pacific Ocean at the end of World War II , was named in his honor . On 7 July , Private Thomas A . Baker ' s position came under attack by a large Japanese force . Although seriously wounded early in the attack , he refused to be evacuated and continued to fight in the close - range battle until running out of ammunition . When a comrade was wounded while trying to carry him to safety , Baker insisted that he be left behind . At his request , his comrades left him propped against a tree and gave him a pistol , which had eight bullets remaining . When American forces retook the position , they found the pistol , now empty , and eight dead Japanese soldiers around Baker ' s body . Baker was posthumously promoted to sergeant and , on 9 May 1945 , awarded the Medal of Honor for his actions throughout the battle for Saipan . He was buried at Gerald B . H . Solomon Saratoga National Cemetery in Schuylerville , New York . On 7 July 1944 , Captain Ben L . Salomon , the battalion surgeon of 2nd Battalion , 105th Infantry Regiment , 27th Infantry Division aided the evacuation of wounded soldiers . After defending his patients from four Japanese soldiers , he manned a machine gun post and effectively repelled numerous enemy forces to enable the evacuation of wounded personnel . When his body was recovered after the battle , 98 dead Japanese soldiers were found in front of his position . For gallantry in battle , Captain Ben L . Salomon was posthumously awarded the Medal of Honor in May 2002 . Salomon was the third Jewish service member to be awarded the Medal of Honor during World War II . Military awards . PFC Guy Gabaldon , of Headquarters and Service Company , 2nd Marine Regiment , 2nd Marine Division , was a Mexican - American from Los Angeles . He is officially credited with capturing more than 1 , 000 Japanese prisoners during the battle . PFC Gabaldon , who was raised by Japanese - Americans , used a combination of street Japanese and guile to convince soldiers and civilians alike that U . S . troops were not barbarians , and that they would be well treated upon surrender . For his outstanding bravery , Gabaldon received a Silver Star , which was upgraded to the Navy Cross . During the war , his commanders had requested that he receive the Medal of Honor for his actions ; however , his initial award was the Silver Star . In 1998 , efforts were re - initiated to secure the Medal of Honor for PFC Gabaldon . The effort was ongoing in 2006 . Aftermath . Although major fighting had officially ceased on 9 July , pockets of Japanese resistance continued . In September 1944 , US Marines began patrols into the island interior in order to bring in civilians and soldiers still holding out in the jungles . A group led by " Rikugun Taii " Sakae Oba managed to evade capture for more than 512 days until surrendering to American forces on 1 December 1945 , three months after the official surrender of Japan . In February 2011 , a film about Oba , " " , was released in Japan . With the capture of Saipan , the American military was now only away from the home islands of Japan . The victory would prove to be one of the most important strategic moments during the war in the Pacific Theater , as the Japanese mainland was now within striking distance of United States ' B - 29 bombers . From this point on , Saipan would become the launch point for retaking other islands in the Mariana chain and the invasion of the Philippines in October 1944 . Four months after capture , more than 100 B - 29s from Saipan ' s Isely Field were regularly attacking the Philippines , the Ryukyu Islands and the Japan mainland . In response , Japanese aircraft attacked Saipan and Tinian on several occasions between November 1944 and January 1945 . The US capture of Iwo Jima ( 19 February – 26 March 1945 ) ended further Japanese air attacks . The loss of Saipan was a heavy blow to both the military and civilian administration of Japanese Prime Minister Hideki Tōjō . According to one Japanese admiral : " Our war was lost with the loss of Saipan . " US Marine Corps General Holland Smith said : " It was the decisive battle of the Pacific offensive [ . . . ] it opened the way to the Japanese home islands . " Shortly after Saipan was taken , a meeting at the Imperial General Headquarters was convened where it was decided that a symbolic change of leadership should be made : Tōjō would step aside and Emperor Hirohito would have less involvement in day - to - day military affairs , even though he was defined as both head of state and the Generalissimo of the Imperial Japanese Armed Forces according to the Meiji Constitution of 1889 . The general staff believed it was now time to distance the Imperial family from blame as the tide of war turned against the Japanese . Although Tōjō agreed to resign , Hirohito blocked his resignation because he considered Tōjō to be Japan ' s strongest war leader . But after Tōjō failed to shuffle his Cabinet due to excessive internal hostility , he conceded defeat . On 18 July , Tōjō again submitted his resignation , this time unequivocally . His entire cabinet resigned with him . Former IJA General Kuniaki Koiso became Prime Minister on 22 July . However , due to the legacy of Saipan , Koiso was nothing more than a titular Prime Minister , and was prevented by the Imperial General Headquarters from participating in any military decisions . Saipan also saw a change in the way Japanese war reporting was presented on the home front . Initially , as the battle started , Japanese accounts concentrated on the fighting spirit of the IJA and the heavy casualties it was inflicting on American forces . However , any reader familiar with Saipan ' s geography would have known from the chronology of engagements that the US Marines were relentlessly advancing northwards . No further mention of Saipan was made following the final battle on 7 July , which was not initially reported to the public . However , after Tōjō ' s resignation on 18 July , an accurate , almost day - by - day , account of the defeat on Saipan was published jointly by the Army and Navy . It mentioned the near total loss of all Japanese soldiers and civilians on the island and the use of " human bullets " . The reports had a devastating effect on Japanese opinion ; mass suicides were now seen as defeat , not evidence of an " Imperial Way " . This was the first time Japanese forces had accurately been depicted in a battle since Midway , which had been proclaimed a victory . After the war concluded , apologists for Hirohito asserted that the order encouraging the civilians of Saipan to commit suicide for benefits in the afterlife had in fact been forged , along with other incriminating orders . Historian David Bergamini considers this unlikely , writing that " half the staff of the palace [ . . . ] would have felt obliged to cut open their bellies if the sacred seals of the Throne had ever been misapplied . " Memorial . Suicide Cliff and Banzai Cliff are recognized as historic sites on the U . S . National Register of Historic Places .