Battle of the Philippine Sea
In June 1944 the US Navy Fifth Fleet operated in the Central Pacific under the command of Adm. RA Spruance; a part of it, on 11 June, began the attack against the Mariana Islands, while the bulk of the Japanese fleet was in a waiting position in Tawitawi (Sulu archipelago in the southern Philippines). That dislocation stemmed from the assumption that the new American target was chosen in the southwestern Pacific, so much so that the Japanese high command at first suspected that the offensive against the Marianas was of a diversionary nature; however he did move the naval forces towards the central area of the Philippines. It being confirmed that American forces had begun landing operations at Saipan, the Japanese fleet crossed the San Bernardino Strait on the evening of June 15, reuniting the following morning with other forces coming from the south and, after having carried out the refueling at sea, he headed towards the area west of the Marianas, to fight the decisive battle. News of the Japanese movements was broadcast by two American submarines. The Japanese fleet under the command of Vice Admiral T. Ozawa consisted of 6 aircraft carriers and 3 light aircraft carriers, 5 battleships, 11 cruisers and 25 destroyers, with two flotilla chief cruisers. On the American side it was decided to continue the landing operations in Saipan under the cover of the naval force called “Task Force 58” under the command of the deputy team. Marc A. Mitscher; that force consisted of 8 large aircraft carriers and 8 light aircraft carriers, 7 fast battleships, 3 large cruisers, 6 light cruisers, 4 anti-aircraft cruisers and 58 destroyers. The American fleet had an aggressive task with respect to the Japanese one, subject to the need to keep close enough to Saipan, to prevent interference in the amphibious operation.
The Japanese plan was mainly based on the use of the air bases in the Mariana Islands: with this concept, the aircraft of the aircraft carriers were launched at distances close to the limit of their range of action with respect to the islands, to get them to arrive as soon as possible in the area of battle and stock up on fuel and weapons in the land bases of Guam, Rota and Tinian, which thus took on a complementary function to that of aircraft carriers, with the advantage of offering non-sinking bases.
On the morning of June 19, the groups of Japanese aircraft, both in directing the landing on the islands and in proceeding to attack the American ships, were intercepted by fighter aircraft. Thus a great air battle took place over the island of Guam; by means of the radar the Japanese aircraft heading against the aircraft carriers were intercepted at a distance of 50 to 60 miles from the targets; moreover, the American fighter aircraft, in addition to arriving promptly in position to cut off the enemy’s route, had an altitude advantage. This produced a disastrous result for the Japanese aviation, so much so that out of 545 aircraft engaged 402 were destroyed, against the loss of 17 aircraft by the US. Only about 40 Japanese airplanes could arrive to attack on ships, but with very little effect. On the same day the two Japanese aircraft carriers Taiho and Shokaku were torpedoed and sunk by submarines.
Only about 100 aircraft remained on the Japanese fleet: therefore those that had been sent to land bases were recalled and the fleet retreated to the west, to refuel and reorganize.
At the same time the American fleet headed west to attack the Japanese one with the air forces. In the late afternoon of the 20th the aerial exploration could spot the Japanese fleet, against which attacks by bomber aircraft and torpedo aircraft were launched from 18 h 20 ‘to 19 h20 ‘encountering a strong anti-aircraft barrage and the contrast of groups of fighter aircraft; however, the Japanese fleet still suffered the loss of two aircraft carriers, two destroyers and an oil tanker; in addition, 3 aircraft carriers, a battleship, 3 cruisers, a destroyer and 3 oil tankers were damaged. American losses in these attacks were limited to 23 aircraft. Another 80 were lost because they ran out of fuel returning to their ships which were about 3,000 miles away.
The great air-naval victory had the immediate effect of the full freedom of action of the American fleet in the operations for the conquest of the Mariana Islands; the consequent change of strategic situation and the disastrous losses suffered by the Japanese navy in the aircraft carriers and pilots had decisive effects on the course of the conflict.
In the battle of the Philippine Sea, the action of American submarines in cooperation with the main surface forces was important, while the Japanese fleet was insufficiently prepared against the attacks of the underwater shipping. Furthermore, that battle marked the failure of the Japanese action plan based on the use of aircraft from ships and island bases; due to the losses suffered in the aircraft carriers, the Japanese navy was forced to base its hopes more and more on the use of ground-based aviation.