The Battle of Saipan was fought between June 15th and July 7th 1944. Saipan held huge strategic importance for both the Japanese and Americans. Saipan was part of the Mariana Islands and its capture would allow the Americans to build runways big enough for its B29 Superfortress bombers to reach mainland Japan and return to their base in Saipan. It also meant that any Japanese forces south of Saipan were cut off from the Japanese mainland itself. The Americans wanted to capture Saipan at all costs but the Japanese, equally aware of its importance, were also prepared to defend the island to the death. The Battle of Saipan proved to be very bloody.
An amphibious landing on the island was preceded by an intense two-day bombardment carried out by the US Navy. Over 165,000 shells were fired at Japanese positions on the beaches that the Marines were going to land on. The first landings on Saipan took place at 07.00 and by 09.00, 8,000 US Marines were ashore. However, they had to fight every inch of the way as the Japanese defenders had placed barbed wire just behind the beaches along with trenches and machine gun posts. By nightfall, men from the 2nd and 4th Marine Divisions had advanced about half-a-mile inland and a beachhead of six miles in width had been created.
The Marines fought off Japanese counter-attacks. The Japanese high command took the decision that the best way to support the island’s defenders was to attack the US at sea. This resulted in the Battle of the Philippine Sea (June 15th 1944) which proved to be a disaster for the Japanese as they lost three aircraft carriers along with many aircraft. Whereas the Americans could replace lost aircraft carriers because of their vast industrial base, the Japanese could not. The loss of the carriers also meant that the Japanese force on Saipan could not be resupplied or reinforced as they were effectively cut off.
Realising that they could not be resupplied, the Japanese commander on Saipan, General Saito, ordered that his men would fight to the last along a defensive line around Mount Tapotchau in the mountainous centre of Saipan. Mount Tapotchau, and the area surrounding it, was riddled with cave complexes. These proved an excellent base for the Japanese to carry out night time hit-and-run raids on the Americans. Casualties on both sides were high and the Americans had to adopt new tactics to clear out the cave complexes. The weapon of choice to complete this task was the flamethrower supported by the artillery. Flamethrowers were used to drive the Japanese out of their hiding holes or to kill them where they were. Those who fled faced an onslaught by artillery.
The end of the battle occurred on July 7th when Saito ordered what was effectively a suicide attack by the remaining able-bodied men under his command. When the attack started these 3,000 men were also joined by many hundreds of the walking-wounded and Japanese civilians on the island. Their attack took the Americans by surprise and the Japanese pushed through the Americans front line. However, once it became clear what was happening, the Americans rallied and the charge resulted in 4,300 Japanese deaths. What was the largest Banzai charge in World War Two had little chance of success against the vast amount of firepower the Americans had on Saipan but it was a clear indication of what the Americans would face the nearer they got to the Japanese mainland.
Saipan was declared secure on July 9th. Nearly 30,000 Japanese soldiers had died trying to defend the island. 3,426 Americans were killed with 13,000 wounded – fractionally fewer than 25% of the 71,000 US soldiers who landed on Saipan. A small group of Japanese soldiers held out in the mountains until December 1945 when they finally accepted that not only the battle but also the war had been lost.
The Battle of Saipan also witnessed another phenomenon few American soldiers had seen in the whole Pacific campaign. 25,000 Japanese civilians lived on Saipan. They had been informed by the Japanese government of the untold horrors that would happen to them if they fell into the hands of the Americans – how they would be brutally treated etc. As a result, and some say as a direct consequence of an order apparently sent out by Emperor Hirohito, over 1,000 Japanese civilians committed suicide as the battle came towards an end. US army film clips exist of Japanese civilians throwing themselves off ‘Suicide Cliff’ to escape the shame of capture and the fear of what the Americans would do to them.
Once the island was secure SEEBEE’s started to construct runways that could be used by the B-29’s. No Japanese position was safe from heavy bombing once these runways were completed. The Japanese population on the mainland now faced an aerial bombardment that brought the war home to them almost on a daily basis. Japanese positions in the Philippines could also be attacked.