The United States invasion of Saipan in the Mariana Islands provoked the Japanese navy to counterattack which resulted in the Battle of the Philippine Sea. The U.S. landing on Saipan combined with the Battle of the Philippine Sea was known as "the greatest carrier battle of the war" and gave the U.S. control of Guam, Saipan and Tinian islands that provided US air bases within range of B-29 bombers targeted at Japan.

Where was the Battle of the Philippine Sea fought?
The Battle of the Philippine Sea was fought west of the Mariana Islands, a chain of 14 islands in the north-west Pacific, about 1,500 miles (2,400 km) east of the Philippines. The Mariana Islands are located east of the Philippines and south of Japan and include the islands of Rota, Saipan, Tinian, Pagan, Guguan, Agrihan, and Aguijan.

Why was it called the Battle of the Philippine Sea?
It was called the Battle of the Philippine Sea because the Mariana Islands formed the boundary between the Philippine Sea and the Pacific Ocean. The conflict is known to the Japanese as the Battle of the Mariana Islands. It was nicknamed the "the great Marianas turkey shoot" by American pilots.

Who won the Battle of the Philippine Sea?
The Battle of the Philippine Sea was won by America when the United States Navy, under Admiral Raymond Spruance defeated the Imperial Japanese naval force under Admiral Soemu Toyoda and Commander of the First Mobile Fleet, Vice Admiral Jisaburo Ozawa. The Japanese navy lost three aircraft carriers and 600 planes. The United States lost 120 aircraft.

When was the Battle of the Philippine Sea?
The Battle of the Philippine Sea was fought between June 19 - 20, 1944.

Why was the Battle of the Philippine Sea important?
The Battle of the Philippine Sea was important because the Japanese lost nearly 500 aircraft and 450 pilots and Japanese naval aviation never recovered from the blow. The last great naval battle of the war, the battle of Leyte Gulf, followed the crushing defeat and the surviving Japanese aircraft carriers, almost empty of aircraft, could only be used as a decoy force and Japanese pilots became involved in Kamikaze attacks.

What was the key to the American success at the Battle of the Philippine Sea?
The key to the American success at the Battle of the Philippine Sea was due to three important factors, better training, better pilots and better aircraft. The Americans were out-producing the Japanese in war machinery and developing superior technology. The American pilots received better training, it was common for Japanese combat pilots to receive less than 50 hours of flight training.

US Force at the Battle of the Philippine Sea: Order of Battle
The Order of battle relates to the units, formations, and equipment. The US Force at the Battle of the Philippine Sea consisted of 7 heavy carriers, 8 light carriers, 7 battleships, 8 heavy cruisers, 13 light cruisers, 58 destroyers, 28 submarines and 956 carrier aircraft.

Japanese Force at the Battle of the Philippine Sea: Order of Battle
The Japanese Force consisted of 5 heavy carriers, 4 light carriers, 5 battleships, 13 heavy cruisers, 6 light cruisers, 27 destroyers, 24 submarines, 6 oilers, 450 carrier aircraft and 300 land-based aircraft.

Casualties and Death Toll
The United States lost 1 damaged battleship and 123 aircraft were destroyed. 76 US servicemen were killed at the Battle of the Philippine Sea. The Japanese lost 3 carriers, 2 oilers, 6 other ships damaged and between 550–645 aircraft destroyed.. The Japanese death toll was estimated at 2,987.

Facts about Battle of the Philippine Sea
The following fact sheet contains interesting facts and information on Battle of the Philippine Sea.

The Battle  of the Philippine Sea was called "the greatest carrier battle of the war" and was larger than the Battle of the Philippine Sea and the Battle of the Coral Sea combined. Refer to Aircraft Carriers for some interesting information.

The conflict is sometimes referred to as the "First" Battle of the Philippine Sea as the Battle for Leyte Gulf in October 1944 is sometimes called the "Second" Battle of the Philippine Sea. It was also given the nickname of the “the great Marianas turkey shoot” by American pilots.

In May 1944, the commander in chief of the Combined Fleet, Admiral Soemu Toyoda, devized a plan,  codename A-Go, in which a major portion of the Japanese navy would move against the enemy in an attempt to crush its carrier power. 

United States invasion of Saipan in the Mariana Islands prompted the Japanese navy to launch a counter-attack aimed at crushing the carrier power of the Americans which resulted in the Battle of the Philippine Sea.

The security of the Marianas Islands was vital to Japan, which had air bases on Saipan, Tinian, and Guam. U.S. troops were already fighting the Japanese on Saipan and any further intrusion would leave the Philippine Islands, and Japan itself, vulnerable to American attack.

Admiral Soemu Toyoda issued orders to Vice Admiral Jisaburo Ozawa to begin operation A-Go and strike the US forces.

The US commanders were Admiral Raymond Spruance and Vice Admiral Marc Mitscher and the Japanese commanders were  and Vice Admiral Kakuji Kakuta

The Japanese put plan A-Go into operation. Admiral Jisaburo Ozawa's First Mobile Fleet moved towards the Philippine Sea to attack the US forces. The plan was for Admiral Kakuta's 500 land-based planes in the Marianas to destroy a third of the American aircraft carriers before the Japanese First Mobile Fleet arrived.

The Japanese plan started to go wrong before the battle even started. Admiral Kakuta's strength had already been greatly reduced by Allied air attacks on June 11-12. and on June 15 the first American troops went ashore, which marked the start of the invasion of Saipan.

On June 18, 1944 the US 5th Fleet commanded by Admiral Spruance and US Task Force 58 commanded by Vice Admiral Mitscher moved into position against Ozawa. Task Force 58 was also covering the landings on Saipan.

The Battle of the Philippine Sea began on the morning of June 19, 1944 as Admiral Ozawa sent 430 planes in four waves against the US ships.

The Japanese planes were picked up on radar. The conflict was a disaster for the Japanese and the ensuing battle became known as "the great Marianas turkey shoot".

Admiral Ozawa had started the battle with 430 carrier aircraft and 43 floatplanes. Only 130 planes returned to the Japanese First Mobile Fleet.

In addition to the 244 planes lost to Ozawa a further 50 land based aircraft were also destroyed. US forces had also destroyed  two regular Japanese aircraft carriers.

As the Japanese fleet retired northward towards safe harbor at Okinawa, it lost another aircraft carrier and nearly 100 more warplanes

Late after noon on June 20, US reconnaissance planes finally sighted Ozawa's ships. Mitscher launched 230 aircraft damaging several vessels and sinking three including the carrier Hiyo

Spruance made a controversial decision when late on the second day of battle decided not to press his attack further. Nevertheless, Japanese carrier aviation was finished for the remainder of the war.

During the two days of the Battle of the Philippine Sea, the Japanese lost 3 aircraft carriers and 2 oilers, and between 550–645 aircraft. The Japanese death toll was estimated at 2,987. U.S. losses totaled 1 damaged battleship and 123 aircraft. The US death toll was 76.

The Battle of the Philippine Sea was known as "the greatest carrier battle of the war" and gave the United States control of Saipan, Guam and Tinian islands providing US air bases within range of B-29 bombers targeted at Japan.