Battle of the Philippine Sea
Decisive American naval victory against Japan
19 - 20 June 1944
author Paul Boșcu, February 2019
During the battle of the Philippine Sea the US Navy inflicted a devastating defeat on the Imperial Japanese Navy. The battle was the largest carrier to carrier battle in history and eliminated Japan's capabilities to conduct future large scale operations. The aerial part of the battle was referred to as the Great Marianas Turkey Shoot by American pilots because of the devastating losses that they inflicted on the Japanese planes.

The Battle of the Philippines Sea was a major naval engagement on the Pacific Front of the Second World War between the US and Japanese navies. The battle took place during the US invasion of the Mariana Islands. The US forces inflicted a severe defeat on the Japanese navy from which it could never again recover. The aerial part of the battle was named by US pilots the ‘Great Marianas Turkey Shoot’ because of the severe disproportion of losses between the Japanese and US forces.

By the summer of 1944 the Americans held the strategic initiative in the Pacific War. Without any source of intelligence on US planning, the Japanese were reduced to guessing where the next blow might fall. The target chosen by the Americans in June 1944 was the Mariana Islands, which would provide bases for bomber aircraft within range of Japan. Admiral Raymond Spruance sent Task Force 58 under Vice Admiral Marc Mitscher to support landings on Saipan with bombardment by carrier aircraft and naval guns.

The Japanese carrier pilots were new and inexperienced; they were shot down literally by the hundreds by far more experienced and better controlled American pilots in what came to be called ‘The Great Marianas Turkey Shoot’. Most of those not downed by American planes were brought down by the concentrated anti-aircraft fire of the battleships.

American submarines had sunk several of the Japanese destroyers before the battle was joined, and sent to the bottom two of the large carriers; one, the Shokaku, had been at the Pearl Harbor raid, the other, the new Taisho, blew up when the fumes of the volatile Borneo oil exploded inside the portion of the ship sealed off after a torpedo hit.

On the afternoon of the following day, Admiral Raymond Spruance located what was left of Admiral Jisaburō Ozawa's fleet and sent his own planes after it, sinking one carrier and damaging two more. Many of the returning American planes had to ditch as they ran out of fuel in the dark.

The Battle of the Philippine Sea, as it came to be known, was a major American victory in which the Japanese navy lost enormously in ships and even more in planes and pilots it could not replace, while United States losses were very low. The victory in the battle, furthermore, made it impossible for the Japanese to cope with General Douglas MacArthur's advance on New Guinea.

The American ability to deploy carriers both in the southwest and central Pacific reflected the extent to which superior American resources, and their effective use, permitted the simultaneous pursuit of more than one offensive strategy, with a likelihood of success and an ability to overcome the defense and resist counter offensives without having to call on reserves from other ‘fronts’. Air power could be applied from the sea as never before, and as part of an effective and well-supported modern combined-arms force.

There were now sufficient aircraft both for a carrier battle and for protecting an amphibious assault, and the fast-carrier task forces, combined with surface escorts, constituted a major operational-level weapon with the necessary tactical cohesion.

By mid-1944 Japan’s situation was not good: her enemies managed to inflict several heavy defeats and to advance further and further towards Japanese territory. In Tokyo, Imperial Japanese Headquarters appointed a new chief, Admiral Soemu Toyoda, for the Combined Fleet. In the subsequent reorganization, command of the First Mobile Fleet, consisting of the surface and carrier battle groups of the navy, went to Admiral Jisaburo Ozawa. Toyoda and Ozawa drew up concurrent plans that eventually fused as Operation A, a plan for the decisive fleet engagement. While the admirals planned, the First Mobile Fleet assembled in the Tawitawi anchorage between Mindanao and Borneo.

The Imperial Japanese Navy entered the campaign with warships at the edge of technological excellence but with serious operational weaknesses. Ozawa’s flagship, the 29,300-ton carrier Taiho, boasted state-of-the-art engines, anti-aircraft armament, radar, an armored flight deck, and internal survivability improvements. Commissioned in 1944, Taiho had been rushed into service with its engineering officer as commander, since no one else had the training to operate the ship; its limited sea trials quickly revealed that its sailors had not mastered the technology. Other warships were put in service with similar shortages of trained seamen in their crews.

The Japanese admirals behaved just as their American counterparts thought they would, which was to mass their forces for a decisive battle somewhere in the Philippine Sea — some 1,500 miles of ocean that separated the Marianas from the Philippines.

Toyoda and Ozawa drove their staffs to provide more operational integration for the decisive battle. The staffs war-gamed and analyzed every phase of the operation. Even the Emperor himself observed one of Toyoda’s exercises. The concept of Operation A reflected the weakened state of the Japanese carrier aviation force, with its improved aircraft but inexperienced pilots, most of whom had less than six months’ solo time. The Japanese aviators had one advantage: their aircraft had greater ranges than their American counterparts, which meant that the carriers could launch attacking flights beyond the range of US Navy air attack.

The First Mobile Fleet grew to impressive proportions: 6 battleships, 9 carriers with about 500 aircraft, 13 cruisers, and 28 destroyers. Important in Japanese plans, the land-based First Air Fleet deployed about 1,000 aircraft to various airfields that would allow its elite torpedo and bomber squadrons to cover the Philippine Sea, protected by escorting Zeros. The Japanese submarine force also redeployed toward the Marianas, but with no real haste.

With aviation gasoline in short supply, the Japanese naval aviators would have to press home their attacks and hope that they could find airfields on Guam, Saipan, and Tinian for refueling. The planners, in fact, counted on the First Air Fleet to strike the most telling blows on the Americans, then land in the Marianas to refuel and rearm before attacking the Americans on the way home. While the air melee was distracting the Americans, the fast battleships and heavy cruisers would rush eastward for a night surface engagement.

The Japanese aimed to destroy the spearhead of the advancing American fleet by concentrating their air power against it. This reflected a more general conviction, also seen in the Midway operation in 1942, that a decisive victory could be obtained on one front, which could overcome the more general role and impact of Allied resources. Japanese assumptions arose from the sway of historical examples that supposedly represented national greatness and, even more, from the role of factors of will in Axis thinking.

There was a conviction that victory would sap the inherently weaker will of opponents and thus give the Axis the success to which they were entitled. Aside from the lack of political understanding underlying this policy, it was anachronistic militarily. Defeat in 1944 on one front would have delayed the Americans, but nothing more; and, by concentrating a target for the Americans, Japanese strategy made it more likely that the American attack would succeed in causing heavy casualties. The Americans had a better and more mobile fleet, a far greater ability to replace losses, and far more capable leadership than the Japanese.

As the battle on Saipan ripened into another bloodbath, the Fifth Fleet and First Mobile Fleet moved to engage each other, Spruance with characteristic caution and Ozawa with characteristic aggressiveness but less tactical information. For the Japanese it was an unmitigated disaster. In total the Japanese lost over 300 aircraft in what became known as the ‘Marianas Turkey Shoot’.

The waves of aircraft sent to attack the American fleet met a sophisticated defense system. Incoming aircraft were detected by radar, allowing the carrier Combat Information Centers to scramble fighters and vector them onto the intruders. The Japanese pilots were less experienced than the Americans and had no aircraft to match the Grumman Hellcats. The few who survived being pounced on by the fighters were shot down by anti-aircraft fire.

The following day, a long-range American air attack in the failing light sank the carrier Hiyo and damaged three others. The Japanese carriers were protected by a screen of Zero fighters, but, as a clear sign of growing Japanese weakness in the air, this was too weak to resist the fighters escorting the American bombers. Although the Japanese still had a sizeable carrier fleet, once again the loss of pilots and carrier-based maintenance crew was a crippling blow. American submarines sank two large carriers, Shokaku and Taiho.

The Americans did not locate the enemy naval force until late in the afternoon. Mitscher decided to launch his aircraft although they would be operating at extreme range and would have to return after nightfall. The attack was largely successful, sinking the carrier Hiyo for the loss of a handful of aircraft, but the return journey proved to be a nightmare for the naval aircrews. Some 80 aircraft ran out of fuel before reaching the US carriers and were forced to ditch in the ocean, although the majority of the aircrews were rescued.

This victory enabled the Americans to overrun the Marianas, a decisive advance into the western Pacific. The islands provided not only sites for airfields, but also an important forward logistical base for the navy and for amphibious operations.

The battle of the Philippine Sea destroyed the Japanese carriers as a fighting force. The losses of aircraft and pilots were even more crippling than the losses of ships. Another step had been taken toward the total dominance of the US Navy in the Pacific.

After the battle the Japanese continued building warships, but their numbers were insufficient and their navy lacked the capacity to resist the effective American assault. It also suffered from poor doctrine, including a lack of understanding of naval air war and an inadequate understanding of respective strategic options. Indeed, the deficiencies in Japanese planning indicated serious systemic failings, including an inability to understand American policy and to respond to earlier deficiencies in Japanese strategy and operational planning.

The campaigning in 1944 saw the collapse of the Japanese Empire in the Pacific. Without air superiority, Japanese units and logistics were highly vulnerable, which ensured a lack of tactical, operational and strategic capability. In addition, the Japanese were fooled by American strategy and deception.