The Battle of the Philippine Sea (マリアナ沖海戦 in Japanese) was a naval air battle that took place during the Pacific Campaign of World War II, pitting the Imperial Japanese Navy and the United States Navy in the Philippine Sea…, near the Mariana Islands, between June 19 and 20, 1944, during the occupation by U.S. troops of the island of Saipan (Battle of Saipan) and the subsequent invasion of the island of Tinian (Battle of Tinian), two Northern Mariana Islands.
This battle, which was part of Operation Forager, ended in a complete disaster for the Japanese forces, who lost almost all of their naval aircraft and two thirds of the aircraft carriers taking part in the battle. This is so much so that American pilots coined the expression The Great Marianas Turkey Shoot for this battle.
As a result of this battle, the Japanese Imperial Navy lost the main part of its combat strength in terms of naval aviation.
After the battle of the Santa Cruz Islands, which had ended the Guadalcanal campaign, in October 1942, the Japanese fleet withdrew to Truk Island, then to the Palau Islands and finally to Singapore, to reorganize and replace the losses suffered.
After the death of Admiral Yamamoto (see Operation against Yamamoto) in April 1943, Admiral Mineichi Koga became the new commander-in-chief of the Imperial Japanese Navy. Japanese naval strategy at that time consisted of defending a security perimeter around Japan, including the Solomon Islands, the Gilbert Islands and the Mariana Islands as far north as the Aleutian Islands (Japanese-occupied Alaskan territory). After the successes of General Douglas MacArthur in the New Guinea Campaign, as well as the American air raids on the Japanese naval base at Rabaul since the fall of 1943, with the consequent attrition of the Japanese fleet, it seemed evident that this defense perimeter could no longer include the Solomon Islands, the Gilbert Islands or the Marshall Islands.
Admiral Koga died in a plane crash in March 1944, and was replaced by Admiral Soemu Toyoda, who commanded the fleet remotely from the capital, Tokyo. The Combined Fleet that had been the pride of Admiral Isoroku Yamamoto had been divided into several groups, and the most important force at Toyoda”s disposal was the 3rd Force, or Mobile Force.
From the end of 1942, the commander-in-chief of the Mobile Force was Vice Admiral Jisaburo Ozawa, an officer considered to be aggressive as well as commanding and knowledgeable.
On May 11, 1944, Ozawa”s Mobile Force left the port of Singapore, setting sail for Tawi-Tawi, an island in the Sulu Archipelago in the Philippines. Toyoda”s main plan was Operation “A” (A-Go): it was to draw the U.S. fleet into the area bounded by the Palau Islands, the Marianas and the Carolinas, where a number of land-based air units were located. The joint action of embarked and ground-based aviation should destroy the US Task Force and thus eliminate any possibility of the latter protecting an eventual Allied landing in the Mariana Islands.
While the Japanese fleet had been awaiting the U.S. attack since mid-May at Tawitawi, it was spotted by U.S. submarines, which began harassing it during its training sorties. Thus, the Yukikaze was damaged by a torpedo hit.
In early June 1944, the Japanese fleet detected the approach of the U.S. Fifth Fleet, and headed to meet it in order, it thought, to proceed with its annihilation.
The U.S. operation was called Operation Forager. Its objective was the seizure of control over the Mariana Islands and especially Saipan (Battle of Saipan) and Tinian (Battle of Tinian), two islands that belonged to Japan as a trust granted by the League of Nations since 1917, as well as Guam (Battle of Guam), an American island since 1899, the largest of the Marianas, located south of the archipelago and which Japan had invaded three days after the attack on Pearl Harbor.
The U.S. Fifth Fleet was composed primarily of landing units (Joint Expeditionary Forces) under the command of Vice Admiral R.K. Turner, and fast aircraft carriers and their escort (Task Force 58 or TF 58) under the command of Vice Admiral Marc A. Mitscher.
On June 11, the U.S. invasion force preceded its main thrust with a series of air raids against the Marianas, with the intention of making the Japanese believe that these islands were the objective of the offensive. This came as a surprise to them, as they thought more likely an attack further south, either on the Caroline Islands or Palau.
The Japanese Mobile Force departed Tawitawi on 13 June for the Marianas. Since it had already been detected by U.S. submarines, and in addition the Japanese secret code had been broken, all movements of the Mobile Force were known to the Fifth Fleet and TF 58.
To complete the picture, U.S. air raids on June 11 on the Japanese airfields at Rota, Saipan, Tinian, and Guam had damaged the air capability of those bases. According to U.S. reports, one hundred and fifty (of the previous total of two hundred and fifty) Japanese aircraft were destroyed on the ground or shot down, compared with the loss of only eleven U.S. aircraft.
On June 14, Spruance received information concerning the possible arrival of Japanese air reinforcements from Iwo Jima and Chichi Jima on the Ogasawara Islands (also called the Bonin Islands). Knowing that it would be several days before confrontation with the Japanese fleet, he sent two Task Groups, Clark”s TG 58.1 and Harris” TG 58.4, in the direction of these islands. The Task Groups arrived there and attacked them on June 16, causing severe damage to the air capabilities of their airfields.
On the other hand, on June 15, the invasion of the island of Saipan began.
On June 17, at about 8 p.m., the Mobile Fleet encountered Admiral Ugaki”s battleship squadron, heading immediately for the Mariana Islands. Despite being in a manifestly inferior situation, the Japanese were confident of success, since their aircraft had a greater radius of action and, on the other hand, they could organize a relay between the carriers and their bases on land, which significantly increased the performance of the aviation embarked on their aircraft carriers.
The Japanese A-GO plan was based on the joint action of both aircraft, the embarked and the ground-based ones. The latter should have destroyed at least one third of the American potential from the outset. However, the reality was that the American bombing had caused serious losses to the Japanese ground aviation, and had also left the corresponding airfields practically unusable. As a consequence of all this, the action of the ground aviation was going to be minimal in the battle that was going to take place, which entailed serious consequences for the air potential of the Japanese Mobile Fleet and for the subsequent development of the battle itself.
On 18 June, Admiral Mitscher had assembled TF 58 near Saipan, and was preparing for battle. Shortly before midnight that same day, Admiral Chester Nimitz sent Spruance a message informing him that the Japanese fleet was approximately 560 km west-southwest of TF 58, and Mitscher requested authorization to move west during the night, to be in a good position to attack at dawn.
Spruance refused to issue such an order, fearing that the Japanese might try to draw his Task Force away from the invasion zone with a diversionary force and then attack his fleet from the flank, thus jeopardizing the landing operations on Saipan. He therefore ordered the Task Force to hold its position, leaving the initiative to the Japanese, and ordered the two Task Grops sent to the Bonin Islands to rejoin the Task Force on 17 June.
Spruance”s immobile stance was criticized at the time (and indeed still is), although it would be interesting to compare Spruance”s prudence at the time with Admiral William F. Halsey”s impetuous pursuit of a Japanese diversionary force during the Battle of Leyte Gulf.
At 0530 hours TF 58 began to launch air patrols. At the same time, Japanese aircraft based in Guam were sending 50 planes in search of the Task Force.
At about 0550 hours a Mitsubishi A6M Zero located TF 58 and managed to radio word of its location before it could be shot down by U.S. aircraft.
Less than an hour later, the rest of Guam”s air forces were regrouping to go out to attack the Task Force.
Since these movements had been detected by U.S. radar, a Hellcat group from the USS Belleau Wood took off for the attack as the Japanese planes were gathering to make their own attack, joined by aircraft from the other islands.
A dogfight ensued, during which 35 Japanese aircraft were shot down. The battle was not yet over when the Hellcats were recalled by their carriers at 10:00.
They had been ordered to return to their carriers as TF 58 had just detected a number of radar contacts 150 miles to the west. This was the first raid of 69 aircraft launched by the Mobile Force, and TF 58 in turn launched almost all of its embarked aircraft.
The launching of this first wave of aircraft at 0800 hours, well in advance of the other waves, was the first mistake made by Rear Admiral Obayashi, who was in command of the carriers of Vice Admiral Kurita”s Van force, and who made the decision to launch this attack without waiting for orders, thus causing the breakdown of any scheme of coherence in the Japanese attack.
The second mistake was made by the Japanese airmen, who broke off their advance when they were 100 km from the Task Force, in order to regroup before the attack. This false maneuver gave the American planes an extra 10 minutes, so that a first group of Hellcats caught up with the Japanese planes 100 km from the Task Force at 10:36 am. 25 Japanese aircraft were quickly shot down, while the Americans had to deplore the loss of only one aircraft.
The remaining Japanese aircraft were immediately attacked by another group of U.S. aircraft, resulting in 16 more Japanese aircraft being shot down. The surviving aircraft attempted to attack two U.S. destroyers, the Yarnall and the Stockham, but failed to cause any damage. One bomb hit the battleship South Dakota, but no Japanese aircraft managed to get close to the U.S. carriers, and only 27 aircraft returned to the Japanese carriers.
Meanwhile, at 0900 hours, Ozawa had ordered his main attack, 129 aircraft launched from Force A carriers, although he did not order Force B carriers under the command of Vice Admiral Takaji Joshima to take off. After his failure to react to Obayashi”s impetuosity, this was Ozawa”s first mistake.
At 11:07 a.m. the second wave of Japanese aircraft is detected. U.S. aircraft hit them within 100 km of the Task Force and 70 Japanese aircraft were shot down before they could reach the U.S. fleet. However, six aircraft attacked Rear Admiral Montgomery”s Task Group 58.2, causing some minor damage to two aircraft carriers. A small group of torpedo planes attacked the USS Enterprise, and a torpedo exploded in its wake. In all, 97 of the 129 Japanese aircraft in this wave were shot down.
A third wave of 47 Japanese aircraft was intercepted at 13:00 hours about 75 km from the Task Force. Seven of them were shot down, and the Japanese turned back, returning the remaining 40 aircraft to their base.
The last Japanese air raid of the day, involving 82 aircraft, was launched between 11:00 and 11:30. The raiding party, however, had received incorrect information about the Task Force”s position and was unable to locate it. The squadron split into two groups, one heading towards Guam and the other towards Rota to refuel. The group flying towards Rota encountered Montgomery”s TG 58.2. 18 of the aircraft were hit by the American fighters, which shot down 9, while a group of 9 bombers attacked the Wasp and Bunker Hill carriers, though without causing them the slightest damage, while eight of the attacking bombers were shot down. On the other hand, the group on its way to refuel at Guam was intercepted by 27 Hellcats as it was preparing to land. As a result, 30 of the 49 Japanese planes were also shot down, while the rest were seriously damaged.
In other words, by nightfall of the first day of the battle, the Japanese Mobile Force had already lost a good part of its ground-based fighter troops in the Marianas and Bonin Islands, and had also lost more than 200 aircraft, which amounted to about half of the carrier-borne aviation.
On June 16, the U.S. submarine Cavalla located one of the Japanese tanker groups, which was following a route north of the Mobile Force. The commander of the Cavalla reported this contact, adding his desire to attack the located tankers, but the Commander-in-Chief, Pacific Submarines (ComSubPac), Vice Admiral Lockwood, ordered him to follow the tankers so that he could locate the main fleet, which occurred the next day, June 17, when Ozawa went to refuel for the last time before the battle. The Cavalla also reported this new location, and set out to follow the Mobile Force.
On June 18, another U.S. submarine, the Albacore, joined the Cavalla. On the morning of June 19, the Albacore attacked, shortly after 0900 hours. She decided to torpedo the Taiho, the Force”s flagship, which had just taken off 42 aircraft as part of the second Japanese wave.
Four of the six torpedoes launched missed their target, and a fifth torpedo was stopped thanks to the sacrifice of a Japanese pilot (Sakio Komatsu) who launched his plane over the torpedo, but the sixth torpedo hit the Taiho. At first glance, the damage did not appear serious, and there was almost no reduction in the ship”s speed.
The Cavalla torpedoed the Shōkaku around noon. Three torpedoes struck the Japanese ship, which was severely damaged. A fire broke out and reached the ammunition magazines at about 15:00, and the Shokaku exploded and quickly sank, taking 1263 men with her; the 570 survivors included her commander, Hiroshi Matsubara.
Meanwhile, the Taiho was suffering from the mistake of a damage control officer who ordered the full power of the ventilation system to be used to expel the aviation gasoline vapors partially flooding the forward elevator shaft from the ship. The order caused the highly flammable fumes to spread throughout the ship, turning it into a floating time bomb, which finally caused an explosion and its sinking at about 17:30 hours; 1650 crew members died out of a total of 1751.
The Task Force sailed westward during the night of June 19-20, aiming to attack the Japanese at dawn. With the first light of dawn on June 20, the TF launched several patrols in an attempt to locate the Mobile Force.
After the Taiho had been hit, Ozawa had transferred his command ensign to the destroyer Wakatsuki. However, the ship”s radio was unable to take on the volume of traffic required for the admiral, who again changed ships, transferring this time to the Zuikaku at about 1300 hours. It was then that Ozawa received the final reports of the previous day”s catastrophic attacks, finally realizing that he had just over 100 fighters left.
However, still believing in the massive presence of ground-based aviation on Guam and Rota (since Vice Admiral Kakuji had concealed in his reports the seriousness of the situation, a problem that was to become endemic among the Japanese forces), he decided to proceed with the marked plan and planned new air strikes for June 21.
The American patrols had difficulty in finding the Japanese fleet, and it was not until late in the day, at 15:40 hours, that Mitscher received a first report of their situation, although it was a confused and unintelligible report. Finally, at 16:05 hours, a second, more clarifying report reached Mitscher”s hands, whereupon he decided to immediately launch a major attack. This decision involved a certain degree of danger, since the Mobile Force was two hours flying time away from the Task Force, and sunset was to occur at about 18:30. The planes took off at 16:20 hours and the attack took place shortly after 18:00”.
The Mobile Force at this time was scattered: planes fell on the tankers and on their destroyers. Force “C” was to the west, Force “B” to the west-northwest, and Force “A,” already decimated by the loss of the Taihō and the Shōkaku, was to the northwest.
Ozawa was only able to launch 35 fighters to protect his fleet, although they were highly experienced pilots, and he also had the anti-aircraft firepower of his ships at his disposal. However, the U.S. assault, with a fleet of 216 aircraft, was extremely powerful, and many of the planes were able to launch the attack.
The first ships to be acted against were tankers, two of which were so badly damaged that they had to be abandoned and sabotaged to cause their sinking shortly thereafter. The carrier Hiyō, attacked by four Avengers from Belleau Wood, was hit by at least one torpedo and sank shortly thereafter. The carriers Junyo and Chiyoda suffered bomb damage, as did the battleship Haruna. Twenty U.S. aircraft were shot down in the course of this action.
In view of the number of aircraft involved in the attack and the poor Japanese response, the balance of the attack was ultimately poor. The weak results were due to the fact that most of the Avengers carried bomb loads and not torpedoes. The only real success was achieved by the Belleau Wood Avengers, which were the only squadron armed with torpedoes.
During the return to the Task Force, some aircraft had to ditch due to damage or lack of fuel. At 20:00, the first planes arrived at the Task Force and there were staggered arrivals until 22:00. Mitscher had made the decision to fully illuminate the carriers, despite the risks of attack by enemy submarines or night bombers, and the destroyers launched signal rockets to help the U.S. planes find their way. Despite these efforts, 82 aircraft were lost, some of which crashed on landing on the carriers, although most of them splashed down, allowing the crews of most of them to be recovered over the following days, thus minimizing the severity of the losses suffered.
That night, Ozawa was ordered by Toyoda to withdraw from the Philippine Sea. The Americans launched in pursuit, and the Mobile Force was again spotted by the Avengers on June 21, although no combat ensued. Spruance then called in Mitscher, as he did not want to jeopardize the Marianas invasion by leaving it without Task Force protection.
The naval battle was over, so that Operation Forager could go ahead, which would bring with it the conquest of the Mariana Islands and especially Saipan, Guam and Tinian, and the consequent construction of air bases that would soon allow the takeoff of the giant American bombers, the B 29 Flying Superfortresses destined to bomb the Japanese metropolitan territory.
The four Japanese attack waves had affected 373 aircraft, of which only 130 had returned to their bases, and many others had been destroyed when the carriers they were on were sunk. After nightfall on the second day, total Japanese losses were three carriers and 395 aircraft, while total American losses were limited to 23 aircraft on the first day and 100 on the second (including the 80 aircraft lost due to night darkness, from which a good part of their crews were to be rescued).
The losses suffered by the Japanese Fleet were irreplaceable, and the Japanese naval air arm could no longer be considered strictly as a force capable of participating in operations. During the battle of Leyte Gulf, a few months later, the aircraft carriers were no longer to be used except as decoys, due to the lack of pilots and aircraft.