In September 1943 IJN Headquarters decided that the time was right to go back on the offensive in the Pacific. Losses from the Battle of Midway had been largely replaced in terms of numbers of carriers, and since the US attacking Japanese held islands on their "island hopping campaign", the lack of planes themselves could be addressed with the addition of strong land based forces. The result was plan A-Go, which would take place some time in early 1944, attacking the US Pacific fleet while it launched its next major offensive. On May 3rd orders for A-Go were sent out, and the waiting began.
On June 11th US carrierborne forces started a series of small strikes on the Marianas, convincing Admiral Toyoda, Commander-in-Chief of the Combined Fleet, that the US was preparing to invade. This came as something of a surprise, as they had expected the next US target to be further to the south, at either the Carolines or the Palaus, and therefore the Marianas were protected with a weak force of only 50 aircraft.
On June 15th the US started their initial landings on Saipan, and Toyoda gave the order for the attack. The main portions of the fleet, consisting of six carriers and several battleships, rendezvoused on 16th in the western part of the Philippine Sea, and completed refuelling on 17th.
The Japanese forces had been sighted on June 15th by American submarines, and by the next day Admiral Spruance, commander of the US Fifth Fleet, was convinced a major battle was about to start. By the afternoon of June 18 Admiral Mitscher's Task Force 58 (the Fast Carrier Task Force) was formed up near Saipan to meet the Japanese attack.
TF58 consisted of five major groups. In front was Lee's Task Group 58.7, the Battle Line, consisting of a large circle of battleships and associated destroyers on picket duty. Just north of them was the weakest of the carrier groups, Harrill's Task Group 58.4. To the east came the three major carrier groups in a line running north-south.
Shortly before midnight on the 18th Admiral Nimitz sent Spruance a message from Pacific Fleet Headquarters indicating that the Japanese flagship was approximately 350 miles to the west-south-west of Task Force 58. Shortly afterwards Mitscher asked for permission to head west during the night to an ideal launch position for an all-out attack on the enemy force at dawn.
However, Spruance refused. Throughout the run-up to the battle he had been concerned that the Japanese would try to draw his main fleet away from the landing area using a diversionary force, and would then make an attack around the flank of the US carrier force - an "end run" - hitting the invasion shipping off Saipan. Instead he placed TF 58 on a purely defensive footing, leaving it to the Japanese to set the pace of the battle.
Spruance was heavily criticised by many officers after the battle, and continues to be to this day.
At 5:30AM TF58 turned north-east into the wind and started to launch their air patrols. At about the same time a number of the 50 aircraft on Guam started up on search missions. At 5:50AM one of these, a Mitsubishi Zero, found TF58. After radioing in its position, he attacked one of the destroyers on picket duty and was shot down.
Over an hour the rest of the Guam forces were being formed up for an attack. They were spotted on radar and a group of Grumman Hellcats from the Belleau Wood were sent to investigate. They arrived while the attack was still only launching from Orote Field. Minutes later additional radar contacts were seen, which were later discovered to be the additional forces being sent north from the other islands. A huge battle broke out, 35 of the Japanese planes were shot down and the battle was still going an hour later when the Hellcats were recalled to the carriers.
The recall had been ordered after a number of ships in TF58 saw a number of radar contacts 150 miles to the west at about 10:00AM. This was the first of the raids from the Japanese carrier forces, with 68 aircraft. TF58 started launching every fighter they could, and by the time they were up the Japanese had closed to 70 miles. However they then made a fatal mistake, and started circling in order to re-group their formations for the attack. This ten minute delay proved critical, and the first group of Hellcats met the raid, still at 70 miles, at 10:36. They were quickly joined by additional groups, and within minutes 25 Japanese planes had been shot down for the loss of only one US aircraft.
The Japanese planes which survived were met by other fighters and 16 more were shot down. Of the remainder some made attacks on the picket destroyers Yarnall and Stockham, but caused no damage. Three or four bombers broke through to the battleship group, and one made a direct hit on South Dakota which caused many casualties but failed to disable her. Not one aircraft of Ozawa's first wave got through to the American carriers.
At 11:07 radar detected another and much larger attack. This second wave consisted of 109 aircraft. They were met while still 60 miles out, and no less than 70 of these aircraft were shot down before raching the ships. Six attacked Rear Admiral Montgomery's group, making near-misses which caused casualties on two of the carriers. Four of the six were shot down. A small group of torpedo aircraft attacked the Enterprise, launching a torpedo which exploded in the wake of the ship. Three other torpedo-planes attacked the light carrier Princeton, but were shot down. In all, 97 of the 107 attacking aircraft were shot down.
The third raid, consisting of 47 aircraft, came in from the north. It was intercepted by 40 fighters at 1:00PM, while 50 miles out from the task force. Seven Japanese planes were shot down. A few broke through and made an ineffective attack on the Enterprise group. Many others did not press home their attacks. This raid therefore suffered less than the others, and 40 of its aircraft managed to return to their carriers.
The fourth raid was launched between 11:00AM and 11:30AM, but were given incorrect directions and couldn't find the fleet. They then broke into two groups and turned to Guam and Rota to refuel. The larger group was intercepted over Guam by 27 Hellcats while landing. 30 of the 49 there were shot down, and the rest were damaged beyond repair. Meanwhile the other group happened across another group of 9 planes had turned for the island of Rota instead, and happened across Montgomery's task group. 9 dive-bombers eluded the fighters and made attacks on carriers Wasp and Bunker Hill, but failed to make any hits. 8 of these aircraft were shot down in the process. Another group of 18 aircraft lost half its number to the American fighters.
At 8:16AM the US submarine Albacore sighted Ozawa's own carrier group, and began an attack on the easiest carrier to reach. This just happened to be the Taiho, Ozawa's flagship. As they were about to fire her fire-control computer failed, and the torpedos had to be fired "by eye".
Taiho had just launched 42 aircraft as a part of the second raid. Four of Albacore's torpedoes were off-target. The pilot of one of the recently-launched aircraft - Sakio Komatsu - sighted one of the two which were heading for Taiho and crashed his aircraft on it. But the last torpedo struck the carrier on her starboard side near her aviation-fuel tanks. At first the damage appeared not to be very serious.
Another submarine, the Cavalla, was able to manuver to an attack position on the Shokaku by about noon. Three torpedos hit the Shokaku, setting her on fire. At 3:00PM the fire reached the bomb magazine, blowing the ship apart.
Meanwhile the Taiho was falling victim to poor damage-control. On the orders of an inexperienced damage-control officer her ventilation system had been operated full-blast in an attempt to clear explosive fumes from the ship. This instead had the effect of spreading the vapours throughout Taiho, and at 5:32 the Taiho exploded and sank.
TF 58 sailed west during the night in order to attack the Japanese at dawn. Search patrols were put up at first light.
Ozawa had transfered to the destroyer Wakatsuki after the Taiho had been hit, but the radio gear onboard was not capable of sending the number of messages needed, so he again transferred to the carrier Zuikaku at 1:00PM. It was then that he learned of the disastrous missions of the day before, and that he had only 100 or so aircraft left. Nevertheless he decided to continue the attacks, thinking that there were hundreds of planes on Guam and Rota, and started planning new raids to be launched on the 21st.
American searches failed to locate the Japanese fleet until 3:40PM. However the report made was so garbled that Mitscher did not know what had been sighted, or where. At 4:05PM another report was received that was clearer, and Mitscher decided to launch a full-out strike even though there was only 75 minutes to sunset. The attack went in at 6:30.
Ozawa had been able to put up very few fighters to intercept - no more than 35 according to later estimates, but these few were skilfully handled, and the Japanese ships' anti-aircraft fire was intense. The US raid, however, contained 216 planes, and the majority were able to press the attack.
The first ships sighted by the US strike were oilers, and two of these were damaged so severely that they were later scuttled. The carrier Hiyo was attacked by 4 Grumman Avengers from the Belleau Wood, and hit by at least one of their torpedoes, and later sank. The carriers Zuikaku, Junyo and Chiyoda were damaged by bombs, as was the battleship Haruna. 20 American aircraft were lost in this strike.
At 8:45PM the first US planes began to return to TF58. Mitscher took the decision to fully illuminate the carriers, despite the risk of attack from submarines and night-flying aircraft, and the picket destroyers fired starshells to help the planes find the task groups. Despite this 80 of the returning aircraft were lost, some crashing on flight decks, the majority going into the sea. Many were nevertheless rescued over the next few days.
That night Ozawa received orders from Admiral Toyoda to withdraw from the Philippine Sea. US forces gave chase, but the battle was over.
The four Japanese attacks used 373 aircraft, of which 130 returned to the carriers, and several more were destroyed onboard the two carriers destroyed on the first day. After the second day the totals were three carriers and 395 aircraft. Losses on the US side on the first day were only 23, and on the second 100, most due to night landings.
The losses to the Japanese were irreplacable. In the Battle of Leyte Gulf a few months later, their carriers were used solely as a decoy due to the lack of aircraft and aircrew to fly them.A-Go
US response
Early actions, June 19
Japanese raids
Submarine attacks
US counterattack
End of the battle