M4A2 Sherman 4th Marine Tank Battalion In combat on Saipan 1944
The Marianas Campaign: Saipan and Tank Warfare, June-July 1944
The capture of the Mariana Islands was pivotal in the Pacific Theater during World War II. The islands – Saipan, Tinian, and Guam – were close enough to Japan to serve as launch points for B-29 bomber raids on the Japanese mainland, making them strategically vital. The U.S. invasion of Saipan on June 15, 1944, was a key battle in this campaign and marked a significant shift in how tanks were deployed and used in the Pacific.
Japanese Defenses on the Marianas
By the time the U.S. began the assault, the Japanese forces on the Marianas had been reinforced, particularly with the addition of the 9th Tank Regiment. This regiment was distributed across the islands: the 1st and 2nd Companies were stationed on Guam, while the 3rd, 5th, and 6th Companies were on Saipan. Additionally, the first large-scale deployment of the Type 1 47mm antitank gun occurred here, although it was largely ineffective against the frontal armor of the American M4 Sherman tanks, it was somewhat more successful against their weaker side armor.
U.S. Marine Armor on Saipan
By this stage of the war, the Marine Corps had reorganized its tank battalions, replacing older light tanks with more powerful M4A2 medium tanks. Each battalion now had three medium tank companies, with a total of 46 tanks. Specialized Satan flamethrower tanks were also introduced, though they were typically deployed in platoon-sized units for support rather than in large numbers.
First Day and Japanese Counterattacks
The Marines landed on Saipan on June 15, 1944, facing heavy resistance from entrenched Japanese forces. The Marine 2nd and 4th Tank Battalions were brought ashore later in the afternoon to support the infantry, providing crucial firepower to clear fortified positions. On the night of June 15, a Japanese Special Naval Landing Force (SNLF) attempted a counterattack, supported by Type 2 Ka-mi amphibious tanks. The attack near Garapan was quickly repelled by Marine tank and bazooka fire, with the Japanese tanks falling victim to superior firepower.
The Japanese mounted a larger counterattack on the night of June 16-17, led by Col. Hideki Goto’s 9th Tank Regiment. In what would become the largest single Japanese tank attack of the Pacific War, 44 Japanese tanks and accompanying infantry charged the U.S. lines. The U.S. Marines, supported by M4A2 Shermans and M3 75mm self-propelled halftracks, responded with overwhelming firepower. The Type 95 Ha-go light tanks used by the Japanese were no match for the American forces. Many Japanese tanks were destroyed by bazookas, 37mm antitank guns, and direct tank fire. Some tanks became bogged down in nearby marshes, while others were knocked out as they approached Marine lines.
Only 12 Japanese tanks managed to escape the initial assault. Most of these were destroyed in later engagements, including a battle on June 24 where M4A2 medium tanks from Company C, 2nd Marine Tank Battalion decisively defeated the remnants of the 9th Tank Regiment near Garapan.
Challenges for U.S. Armor
The terrain of Saipan allowed for more extensive use of tanks than in previous Pacific battles, but tank losses were still heavy. Japanese artillery and magnetic mines proved to be effective at disabling U.S. tanks. Japanese mine teams learned that placing magnetic mines on vulnerable points, such as the sponson fuel tanks, could disable or destroy an M4A2 tank. However, in several cases, the diesel fuel in the M4A2’s fuel tanks did not ignite, sparing the crew from catastrophic fires.
The battle highlighted the need for better cooperation between infantry and tanks. U.S. forces quickly adapted, and communication between tank commanders and infantry improved, aided by the introduction of telephone systems mounted on the rear of the tanks, which allowed infantry to communicate with tank crews during operations.
The Role of Flamethrower Tanks
The Satan flamethrower tanks, based on the M3 Stuart light tank, were deployed in Saipan to clear Japanese bunkers and entrenched positions. However, they proved to be less effective than hoped. The flamethrowers had limited range and reliability, and the cramped interior of the light tank made operating the flamethrower difficult for the crew. Additionally, communication problems due to radio interference from the flamethrower’s ignition system hindered coordination with other units.
Despite these limitations, flamethrower tanks became more widely used as the battle progressed. By the final stages of fighting on Saipan, their utility in clearing Japanese positions was recognized, although it was clear that the Satan tanks would need to be replaced by a more effective design in the future.
The battle for Saipan, declared secure on July 9, 1944, marked a turning point in the Pacific War. The versatility and firepower of the M4A2 Sherman proved invaluable in overcoming the Japanese defenses, and the importance of tank-infantry coordination became more apparent. While the Satan flamethrower tanks received mixed reviews, the experience on Saipan underscored the need for a more robust and reliable flamethrower tank in future campaigns. The battle also demonstrated the overwhelming superiority of American armor and firepower over the lightly armed and armored Japanese tanks in the Pacific.