Although the battle for Midway atoll would not begin until the morning of June 4th, 1942, US Army Air Force B-17s operating from the island found and attacked the Japanese Second Fleet, the ships tasked with the actual invasion, on the third. The Army pilots’ bombs all missed, but at least part of the Combined Fleet had now been decisively located and identified. At 1AM on the morning of June 4th, a Navy PBY Catalina flying boat successfully torpedoed a Japanese oil tanker that was part of the Second Fleet. This would be the only time during the entire battle that a U.S. air-launched torpedo would find its target. This was due to the Mark 13 aircraft torpedo, which was initially an abysmal failure. It was not until 1944 that a reliable version of the torpedo would be available.
Vice Admiral Chuichi Nagumo, in command of the Striking Force of four aircraft carriers, ordered the first raid on Midway launched at 4:30AM on June, 4th. He also launched fighter aircraft to defend his carriers in case the Americans showed up unexpectedly and eight search aircraft to search for the U.S. carriers. He kept half his aircraft in reserve in case the exact location of the American task force was ascertained. This was in accordance with established Japanese doctrine, but the presence of those aircraft on the four Japanese flight decks would become crucial as the battle unfolded.
Unbeknownst to Nagumo, U.S. Navy, Marine Corps, and Army Air Force bombers and dive bombers were on the way to attack his carriers. They had no fighter escort because the few fighters available were need to defend Midway against the incoming Japanese strike. As a result, they were badly mauled without doing any damage to Nagumo's force.
On Midway, meanwhile, the Japanese strike did heavy damage but did not take the installation out of commission. As long as the atoll could be used as a base for aircraft, the planned invasion of June 7th would be in danger. Midway would have to be attacked again. Nagumo ordered his reserve aircraft armed with general purpose bombs fit for a land attack.
Forty-five minutes later, a scout plane reported sighting a sizable American naval group to the east but gave no estimate of size, direction, or speed. Nagumo demanded more details, but did not receive a reply for another forty minutes. This time lapse was critical: by the time the Japanese admiral knew the approximate size of the American force, the aircraft he had dispatched for the first Midway strike were returning, low on fuel. Nagumo had several options, none of them ideal. First, he could let the returning strike aircraft ditch in the ocean while his crews re-armed his reserve planes for a naval attack. Second, he could launch his reserve aircraft with the weapons they had and hope the general purpose bombs would do at least some damage to the American carriers; he could then land the returning strike aircraft. Third, he could land the strike aircraft as soon as they arrived, clear the flight decks, then launch his reserve aircraft against the American force. The third option would take the most time but it would allow the reserve force to be properly armed. Nagumo chose option number three, ordering his crews to continue arming his reserve force for a naval strike while they waited for the Midway strike aircraft to return.
More than 200 miles away, the American commanders faced their own set of problems. The Japanese carriers had been spotted early on the morning of the 4th and the order to launch an attack came at 6:00AM. One problem after another caused delays, so that the three carriers ended up launching their aircraft at different times. Instead of waiting for the entire force to assemble, Admiral Spruance ordered the aircraft to proceed to their targets as piecemeal squadrons. They would arrive over the Japanese carriers in several groups and from different directions, but this was a risk that had to be taken if the Japanese Striking Force was to be neutralized as early as possible.
Two squadrons of TBD Devastator torpedo bombers, slow and obsolete, attacked the Japanese carriers separately at 9:20 and 9:40. One of the squadrons, VT-8, lost all 15 planes; only one man survived. The second squadron, VT-6, was almost a complete loss. Once again, the Japanese carriers were not damaged.
At 10AM, a third torpedo bomber squadron, VT-3, was spotted by Japanese outlooks. Japanese fighters, fresh from killing the two previous squadrons, zoomed off to decimate the third. They were low on altitude, ammunition, and fuel.
What happened next can be attributed to blind chance, luck, or divine intervention. While the Japanese fighters roared away low over the waves to attack VT-3, three American dive bomber squadrons came in high from the northeast and southwest. They had experienced trouble finding the Japanese carriers, but their delay contributed to their success. Beginning at 10:22AM, the American dive bombers went to work on the Japanese ships, who were without fighter cover. Five minutes later, three aircraft carriers of the Imperial Japanese Navy were out of commission and would soon be abandoned and scuttled. The tide of the Second World War in the Pacific had turned.
The fourth aircraft carrier, Hiryu, was saved by the bravery and discipline of her damage control teams. She launched a counter-attack against the American carriers and punched Yorktown (the carrier which had taken so much damage at Coral Sea) with two torpedoes, which caused her to lose power and develop a severe list to port. Hiryu was then attacked again by American dive bombers, this time fatally.
As the sun dipped below the horizon, both sides debated their next move. Ultimately, and after much deliberation, Admiral Yamamoto ordered a withdrawal of the entire Combined Fleet. His losses had been severe and even though a night surface action against the Americans would have undoubtedly been successful, there was no guarantee he could find the American task force before sunrise would allow them to once again launch aircraft.
Much has been made of Admiral Spruance's decision to retreat to the east instead of pursuing the Japanese. However, it's important to remember that he had one severely damaged carrier, Yorktown, which would ultimately be sunk by a Japanese submarine on June 6th. He did not know the composition of Yamamoto's entire force and he did not want to risk a night surface engagement with Japanese battleships against his few heavy cruisers. He had gained a significant victory, and that was enough.
Although the war would continue for another three years, the Imperial Japanese Navy would never again roam the Pacific as it had before June, 1942. Japan's industrial base could not support a protracted war and her manpower resources could not produce qualified naval pilots fast enough to replace those lost at Midway and in the later campaigns of the war. Pre-war planning had called for the Combined Fleet to meet the American Pacific Fleet somewhere in the Pacific and decide the contest in one giant naval battle. After June, 1942, that possibility was gone and Japan could not find victory with any other.