The Battle of Saipan
Chapter 33
“When we lost Saipan, Hell is on us.”
As the Allies landed in Normandy, another amphibious invasion was launching on the other side of the world. The next major battle of the Pacific War was to take place on the island of Saipan, in the Marianas chain. This operation was to commence the main thrust of the American island hopping campaign toward Japan itself, and would thus strike for the first time at an island that had been under Japanese rule before the war. Saipan, along with adjoining islands of Tinian and Rota, had become Japanese territories after their seizure from Imperial Germany in the Great War, and had been expanded with the conquest of the US Territory of Guam in 1941.
Admiral Nagumo with his officers on Saipan
The Marianas also represented the edge of what the Japanese command considered to be the inner defensive zone of the Empire, with a Japanese civilian population residing there as well as the strategic importance imparted by the location of the islands. American plans were to seize them as a location from which to base their long range B29 bombers, and thus escalate their nascent bombing campaign on Japan itself, as well as using them as a springboard for ground invasions ever closer to the Home Islands.
A knocked out Japanese coastal gun on Saipan
To defend the island, the Japanese had allocated a substantial Imperial Army component to augment the naval garrison, amounting to over 30,000 men. They were supported by coastal artillery and armored units, although plans to fortify the interior of the island were not initiated before the invasion, leaving the only signigificant defensive works along the beaches. The fierce rivalry between the Army and Navy further complicated matters, with Army officers on the island refusing to comply with the orders of the commander of the island, Admiral Chuichi Nagumo.
US Navy SBD Dauntless dive bombers over Saipan
The American invasion force earmarked for the invasion, codenamed Operation Forager, mustered two Marine divisions and one Army division, along with a quantity of Sherman medium tanks as well as specially modified M3 Stuart light tanks equipped with flamethrowers. Air support was to be provided by the fifteen carriers of the US Navy’s Fast Carrier Task Force, along with supporting naval gunfire support from numerous warships.
5’’ guns aboard the battleship USS New Mexico fire on Japanese positions on Saipan
The landings were prefaced by large scale aerial attacks, which managed to destroy most of the Japanese planes stationed in the Marianas on the ground. Subsequent attacks were made against numerous military and infrastructure targets, and were followed on 13 June by naval bombardment of the coastal defenses, although this was only marginally effective.
Black smoke rises from targets on Saipan after they are hit during the preliminary air and naval bombardment of the island
The invasion itself began on 15 June, with the Americans coming ashore in force around Charan Kanoa on the southwestern sector of Saipan, with almost ten thousand Marines coming ashore in the first wave. Opposition was heavy, especially from Japanese artillery positioned in the hills overlooking the beaches, pre-ranged for accurate fire on the coral reefs that snagged the Marine amtracks as they crawled toward the shore. Despite all this, the Marines mad acheived a beachhead by the end of D-Dayhe defenders mounted numerous small-unit counterattacks throughout th day and night, but were unable to do anything more than contain the beachheads around the town of Charan Kanoa.
Amtracks loaded with Marines head for the beaches, as the cruiser USS Indianapolis fires a salvo inland
The following day, 16 June, the US Army’s 27th Infantry Division came ashore, and the Americans began to push to link the two beachheads around Charan Kanoa. The Japanese launched another, more powerful counterattack that night, with an armored force backed up by infantry. This was repulsed with heavy losses, in particular to the Japanese tanks, which proved no match for the American Shermans.
Marines o the first assault wave on the beach
On the fourth day of the battle, Japanese forces began to withdraw to a defensive line in the island’s interior, amidst the mountains and caves. The Americans launched their attacks on this line on the 21st of June committing all three of their divisions into the assault. Fighting was intense, but while the Marine divisions on the flanks made slow progress, the Army’s 27th Infantry found itself stalled, leading to the relief of its commanding officer in a controversial episode. Despite this, it would take almost a week to clear the area known to GIs as “Death Valley”.
A knocked out Japanese Type 97 medium tank
The main Japanese airbase on the island, Aslito Field, had been captured by Army troops on 18 June, and USAAF fighter-bombers began operating from it three days later, increasing the pressure on the Japanese defenders. Infantry pushed into the mountains with heavy artillery support, clearing the caves with flamethrowers, or simply bypassing them after sealing their entrances with charges. Modified M3 Stuart light tanks equipped with flamethrowers, designated “Satans” proved particularly useful in assaulting these positions.
A modified M3 Stuart “Satan” fires its flamethrower at Japanese positions
On 26 June a Japanese force that had been isolated on the southernmost point of the island broke through the American lines and attack Aslito Field, destroying one US fighter before being overrun by the Marines in the area. By the end of the month Japanese communications were collapsing, as were their supply caches. The Americans managed to breach the defensive lines in the mountains on 20 June, leaving the remnants of the Japanese defenders to pull back to the north for their last stand.
A Japanese zero fighter captured on Aslito Field
This withdrawal did not go as planned, however, as the breakdown in communications meant that only some Japanese units actually received their orders to pull back. Others simple remained in place and were destroyed piecemeal, while the Americans advanced northward, pushing the Japanese up against the sea. Heavy resistance was offered at Makunsha, but the Americans simply began to move around it to isolate the defenders there.
Marines lob hand grenades at Japanese troops on Saipan
Realizing the situation was untenable, the commander of the IJA troops on the island, General Yoshitsugo Saito, issued orders for a final, suicidal “Banzai” charge, to take place before dawn on 7 July. Despite his statement that he intended to join in the attack, the General instead committed Seppuku (ritual suicide) that night. Admiral Nagumo, the nominal theater commander, also shot himself in a cave around this time (some debate still exists as to the exact time and location of these suicides).
Marines advance behind a Sherman tank
The Banzai charge that followed on the morning of 7 July was to be the largest conducted in the Second World War, with up to 3,000 Japanese soldiers gathered together, including wounded who were still capable of walking. In the resulting attack two battalions of the 27th Infantry Division were overrun an effectively destroyed, with Lt. Colonel William O’Brien making a valiant last stand with his men. O’Brien utilized two pistols before manning the machine gun on a disabled jeep until the swarm of Japanese overcame his position. He would receive the Congressional Medal of Honor posthumously for his stand.
A Marine bazooka team on Saipan. These weapons proved extremely effective against Japanese armor during the battle
The Japanese charge included their last remaining tanks along with infantry, led by officers with drawn swords. As they reached a Marine artillery battery after overrunning the Army units the gunners fired their howitzers directly into the mass of attackers before being forced to destroy their guns and retreat. In the end, the Japanese took over a thousand yards before being halted, and killed over 400 Americans and wounded more than 500 more. Including those found dead in the Japanese rear from suicide, Japanese casualties numbered over 4,000 by the evening of 7 July.
A patrol during the mop-up operations following the mass Banzai attack
This marked the end of major organized Japanese resistance on Saipan. Despite this, casualties continued to mount amongst the civilian population. Driven by a desperate fear of the American barbarians as well as their own straggling soldiers, large numbers chose to throw themselves from cliffs despite the efforts of the Americans to prevent it. This action in the first encounter of Japanese civilians in the war would provide a grim foretaste of what was to come.
The ruins of Garapan, the seat of the Japanese administration
The Battle of Saipan was a terrible and bloody affair. The destruction inflicted upon the island was widespread, and almost half of the civilian population lost their lives in the twenty-four days of fighting. The Americans sustained almost 4,000 killed and over 13,000 wounded, while the Japanese military would see 1,800 of their garrision of over 31,000 taken prisoner, with almost all the remaining men dead by suicide or enemy action. A small number took to the hills, where they would mount a guerilla war for the duration of the conflict.
A chaplain stands at an altar set up on a wrecked Japanese tank
The ramifications of the defeat at Saipan were felt at the highest levels of the Japanese government. The Emperor himself had taken an interest in the defense of the island, and was angered by its loss. He summoned an emergency meeting with the Imperial General headquarters to discuss a counteroffensive to retake the island, but this proved impossible. The humiliation led the Emperor to lose confidence in Prime Minister Hideki Tojo, prompting him to resign along with his entire cabinet. He was replaced by General Kuniaki Koiso, the Governor General of Korea. In so doing, the Japanese government tacitly conceded that victory was no longer possible, and instead their war aims shifted to achieving a favorable settlement before they were destroyed by the Allies.
Marines stand at the wire of an internment camp for Japanese civilians on Sapian
Meanwhile, the US Army Air Force had begun construction work on expanding the airfields for use by B29s before the island was even secure. With only 1,200 miles to Japan, the capture of Saipan placed all of the Home Islands within reach of American bombers. The USAAF thus stood poised to unleash a strategic bombing campaign akin to that which was by now pummeling Germany around the clock. In Japan, mandatory evacuations went into effect for children, removing them from the cities that the authorities now new would be subjected to heavy air raids. Even the Japanese press was allowed for the first time to acknowledge that the war was going poorly, but despite all of that, the Emperor and his ministers remained convinced that not quite all was lost, and capitulation remained unthinkable.
