The A-GO plan for defeating America in a decisive naval battle required a combination of successful attacks on US ships from carrier planes launched from the west and from land-based planes in Guam and Truk and the Bonins hitting the ships from the east. Unfortunately for Japan, Task Force 58 raids throughout May and early June had reduced available enemy aircraft to a fraction of their strength. Task Group 58.1 (Boston) and 58.4 had just destroyed 100 planes on the Bonins two days before – planes to be used in A-Go. When the Japanese Carrier forces launched their attacks on June 19, they expected 500 fighter planes to hit the Americans from the backside while their planes attacked from the West. Unknown to them, less than 100 total planes were left on the Marianas. American fighter groups reduced what was left all day long in constant sweeps over airfields on Guam, Tinian and Saipan.
The Japanese carriers were too far away from the Americans (more than 350 miles) for their pilots to attack and return to refuel, so the plan was for planes to bomb American ships, land on Guam, refuel, and drop more bombs on their return. Throughout the morning, wave after wave of Japanese Zeroes approached the Americans. They were met with experienced and organized carrier pilot Combat Patrol groups that engaged them in spectacular dogfights. All day long, the men aboard the Task Force ships watched planes and pieces of planes drop, twist and burn into the sea around them. Most Zeroes never got near the ships, but those that did evade the dogfights were met with curtains of steel thrown up by the ships. The few lucky ones to make it past the ships were out of gas and headed for Guam – only to encounter fighter groups sweeping the airfields.
By the time the sun set, the Japanese Navy had lost 265 planes and pilots. The day quickly came to be known as the Marianas Turkey Shoot. US losses were 27 pilots and crewmembers. An additional 50 or so land-based planes were destroyed on the ground on Guam.
Other losses for the day: 27 sailors and 4 officers died or were wounded on American ships. 3,000 Japanese sailors and two aircraft carriers perished after being torpedoed by American submarines that had detected the movement of the Japanese Fleet earlier that morning.