The Battle of the Philippine Sea was mainly an engagement between the fleets of aircraft carriers of the United States and Japan, resulting in the most categorical American victory in the Pacific War, after the Battle of Midway.
On June 15, 1944, the Americans invaded Saipan, part of the Mariana Islands in the Western Pacific. Realizing that losing the Marianas would bring Japan within the range of the American strategic bombers, the Japanese decided to attack the U.S. fleet, hoping to change the course of the war in their favor through a decisive battle.
However, even without taking into account qualitative aspects, the Japanese started off with the second chance.
By historicair [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/) ], via Wikimedia Commons
On June 19, the Japanese launched a series of air raids on the U.S. fleet, first with aircraft based in the Mariana Islands, then with carrier-based aircraft. Being alerted by radar, the Americans directed accurately combat air patrols of Grumman F6F Hellcat fighters towards the enemy planes. The Hellcats were better protected, faster and more maneuverable at higher speeds than their Japanese opponents Mitsubishi A6M "Zero".
The U.S. fighters performed admirably, shooting down most of the Japanese planes with minimal losses. The Japanese aircraft that had managed to escape the Hellcats came across the antiaircraft guns of the U.S. ships, which benefited from an invention with devastating effects - the proximity fuse. On the first day of the battle, the Japanese lost about half of all aircraft at their disposal, succeeding only to damage the battleship USS South Dakota.
The American submarines had a major role in the battle. While the Japanese aircraft were annihilated in their attempt to hit the American fleet, the Japanese received the shock of losing two fleet carriers, following the attacks of U.S. Navy submarines.
Near sunset of the day of June 20, 1944, aircraft from U.S. carriers attacked the Japanese fleet located at the limit of their range, managing to send to the seabed one fleet carrier (it was already the third Japanese fleet carrier sunk).
Problems arose at the returning to the U.S. carriers when many aircraft ran out of fuel, some crashing into the sea. Hence came the biggest American losses, but most of the pilots were rescued.
The outcome of the battle reduced greatly in importance the aircraft carrier fleet of the Imperial Japanese Navy, which it will never recover until the end of the war.