Since World War I, the Marianas Islands, along with the Caroline Islands and the Palau Islands had constituted Japan’s main line of defense and were heavily fortified. In 1943 and for some time in 1944, the Allies conducted successful campaigns to capture many of the Island chains in the Pacific: The Solomon Islands, the Gilbert Islands, and the Marshall Islands. This line had to be broken in order to begin operations directly against Japan and the Philippines.
The Boeing B-29 Superfortress, recently introduced into service, had a range of 1,500 miles, and as such needed a fairly close base of operations for targets in Japan, and the Marianas Islands filled the need perfectly. Thus Admiral Nimitz’ Central Pacific Command were ordered to take the Marianas. The bombardment began on Saipan on 13 June 1944, with around 160,000 shells fired from fifteen battleships.
By 0700 on 15 June 1944, 8,000 Marines landed on Saipan’s west coast. The Japanese had placed flags in the bay to help them estimate range and with this advantage they were able to destroy around twenty amphibious tanks, but by the end of the day the Marines had established a beachhead. The next day the Army’s 27th Infantry Division landed and began the struggle for the Aslito airfield. The Japanese counter-attacked at night but were repulsed with heavy losses, and on 18 June the commander of the Imperial Japanese Army, Yoshitsugu Saito, abandoned the airfield.
Saito expected the Americans to attack the Caroline Islands first, and had prepared an operational plan – A-Go – to provide naval and air superiority and reinforce their garrisons there. When they recovered from their surprise, they attempted to use the A-Go force to counter-attack the US Naval forces around Saipan. However, the disastrous battle of the Philippine Sea caused the loss of three aircraft carriers and several hundred planes, and as such, the Japanese garrisons in the Marianas were isolated and beyond help. There would be no hope of either supplies or reinforcements.
As hopeless as it was, the Japanese nevertheless organized a fairly effective defense and were determined to fight to the death. Saito organized his troops around Mount Topochau in the central region of Saipan’s mountainous area, from which they defended the island. The fighting was very intense, and the Japanese utilized the same techniques later seen on Iwo Jima, hiding in the many caves during the day. At night they emerged to carry out raids against the Americans, and they eventually developed tactics to utilize flame-throwers to clear the caves.
Saito ordered his remaining soldiers forward on a suicide charge, then committed hiri-kiri, killing himself. Several hundred Japanese civilians jumped from cliffs to kill themselves rather than be captured, and efforts to stop them were unsuccessful.
Saipan was the setting for the movie “Hell to Eternity,” starring the late Jeffery Hunter as PFC Guy Gabaldon, an Hispanic from Los Angeles, California who was raised in a Japanese-American household and as such was fluent in Japanese. PFC Gabaldon was credited with taking more than 1,000 Japanese prisoners during the campaign, and was awarded the Navy Cross.
Once Saipan was taken, it was made into a base for further excursions into the Marianas as well as the invasion of the Philippines that October.