The island of Saipan in part of the Mariana Islands lies southeast of Tokyo at a distance of 1,450 miles. Its capture was always part of War Plan Orange because of its strategic importance. The capture of the Marianas (Saipan, Tinian, Rota, and Guam) ensured an open sea lane for logistics support from the mainland United States. Guam became one of the major supply depots in the Pacific from August 1944 to the war’s conclusion. Even today every branch of the US military operates out of Guam – notably Submarine Squadron 15/Los Angeles Class fast attack submarines and Seal Team One.

However the real prizes were Saipan and Tinian. Their location allowed the US and Allies to build multiple airfields for the B-29 Superfortress bomber which initiated sustained bombing of Tokyo and the Japanese home islands for the first time.

While Guam had been a U.S. colony, Saipan had been a Japanese colony since it was ceded to Empire of Japan by the League of Nations as a part of its mandated territory of the South Seas Mandate that transferred all Pacific territories to WWI allies – of which Japan technically was one.

Immigration began in the 1920s by ethnic Japanese, Koreans, Taiwanese and Okinawans, who developed large-scale sugar plantations. The South Seas Development Company built sugar refineries and extensive infrastructure (port facilities, waterworks, power stations, etc. and Shinto shrines. By the time of the June 1944 invasion, Saipan had a civilian population of 29,348 Japanese settlers and 3,926 Chamorro Islanders.

Never before in the Pacific War had the Allies invaded an island with substantial civilian populations. Planners did not know what to expect. On Saipan large numbers of civilians were encountered as active combat members, as well, large numbers of Japanese civilians would die by their own hand rather than be captured by allied soldiers. Was this an isolated instance or was this a harbinger of what to expect on all remaining island invasions – especially any potential invasion of the Japanese home islands? What happened on Saipan influenced military planners for the remainder of the war. What happened on Saipan became a new category of moral scars carried by the marines and soldiers of the Saipan operation.

Pre-Invasion

A submarine blockade was part of a broader U.S. strategy to cut off the Saipan garrison from reinforcements and supplies. In the months leading up to the invasion U.S. submarines aggressively targeted Japanese convoys approaching Saipan sinking transports and troop ships. To give one a sense of the scale, the transport ship Toyama Maru was sunk in June 1944 by USS Sturgeon with 5,600+ troops killed. The Japanese garrison on Saipan, approximately 30,000 troops, was effectively isolated without meaningful resupply. The allied experience at Guadalcanal, New Guinea, Biak, Tarawa and others left no doubt that the garrison would never surrender but would fight to the death with a single goal in mind: inflict as much death and destruction on US forces as possible to (a) delay further westward advance toward the home islands and (b) discourage U.S. homefront from further support of the war. It was a lethal legacy already seen that would play out in this and every subsequent engagement.

What was unclear was what would be the role and fate of Japanese civilians.

Battle of Saipan: Civilian Deaths

The Japanese civilians on Saipan had been indoctrinated as to the fate that awaited them should they be captured by Allied, especially American forces. The civilians were told that the Americans were barbaric and would bruttaly torture all prisoners, both military and civlian. The soldiers were trained and formed in the ethic of Bushidō, the samurai code that emphasized honor, loyalty, and death over surrender. While no such code was incumbent upon civilians per se, they were encouraged to embrace Gyokusai. The term comes from the ancient Chinese saying: “Better to be a shattered jewel [broken pearl] than an intact tile.” This expresses the idea that honor and integrity are worth dying for, even if the cost is destruction. The civilians were instructed to embrace this ethic and offer their lives for the glory of the Divine Emperor.

Intercepted message traffic revealed that the Emperor sent a message to encourage the civilians on Saipan to not be tempted to surrender. In the message he authorized the Saipan commander to promise civilians an equal ‘spiritual status’ in the afterlife with those of soldiers perishing in combat.

The most infamous incident of civilian deaths occurred at Marpi Point. As American forces pushed the Japanese combatants north, thousands of Japanese civilians—many of them women and children—fled to the cliffs at Marpi Point. From July 9 to July 13 hundreds of civilians jumped or were forced to jump from the cliffs to their deaths. Others died by grenade, suicide pacts, or murder-suicides. The total number of civilian deaths is estimated between 800 and 1,000, though exact numbers are uncertain. U.S. troops, shocked by the mass suicides, attempted to stop the civilians by calling out with loudspeakers in Japanese, offering food and safety. In some cases, they were successful in rescuing civilians, but the scale of panic and despair overwhelmed efforts to prevent the tragedy.

However, the most lethal legacy was the July 7th banzai charge. General Saito Yoshitsugu, seeking to inflict as much loss of allied life as possible before his inevitable defeat, ordered a suicide charge of some 4,000 members of the IJA and 55th Naval Guards – as well as approximately 1,000 civilians – to charge the allied lines held by the the battalions of the 105th Regiment of the 27th Infantry division (as well as elements of the 10th Marine Artillery Regiment). The loss among allied soldiers was catastrophic. The loss of Japanese life was 97%.

One army soldier described the charge as like being in the middle of a western cattle stampede as the charge broke through allied lines. The presence of women and children carrying primitive weapons was noticeable. 

The new experience of warfare in the Pacific was impactful on the soldiers and marines who witnessed these events, it was impactful on allied leadership and planners – noting that the Japanese were blurring the lines between military and civilian ranks on the battlefield. This experience was transmitted home in news reports and letters to families.

Civilians – After Fighting

Most of the civilians on Saipan survived the invasion. An estimated 90 percent are believed to have survived. The civilians encountered by the Americans were interned in camps. Here the military authorities could keep them away from the fighting as well as provide food and shelter as well as health care. After the fighting was over, authorities opened schools for the children. The camps held 13,954 Japanese, 1,411 Koreans, 2,966 Chamorros and 1,025 Carolinians at the end of the War (September 1945). 

Conditions in the camps were “military like” in structure and appearance, but conditions were clean and  food was adequate. When the island was secured, families were allowed to leave the internment camp during the day to raise vegetables. The camp had an improvised Buddhist temple which the Japanese also used for Shinto religious ceremonies. 

There were a large number of orphaned children who survived the fighting. Most were repatriated to Japan in 1946 but some were adopted into Chamoran families and remained on Saipan.

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Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives.