In May 1942, things were going Japan’s way. Since their surprise attack on U.S. forces at Pearl Harbor the previous December, the Japanese had struck Allied targets across the Pacific and Far East, seizing Burma (Myanmar), the Dutch East Indies (Indonesia) and the Philippines, as well as Guam and Wake Island.

As a knockout blow, the Imperial Japanese Navy, led by Admiral Isoroku Yamamoto, plotted a large-scale attack on the strategically important U.S. naval and air base on Midway Atoll, two tiny islands in the central Pacific. If successful, Yamamoto believed, the Midway attack would crush the U.S. fleet, winning the Pacific War for Japan.

Things didn’t turn out that way.

Instead, it was the Japanese who were caught off guard on June 4, 1942, and the Americans who would go on to score a momentous victory in the Pacific theater. Here are five little-known facts about the Battle of Midway, and its impact on World War II in the Pacific.

Radar gave the U.S. forces a huge advantage.

The Battle of Midway
The National Archives
A torpedoed Japanese destroyer photographed through the periscope of the U.S.S. Wahoo.

In addition to naval codebreaking that gave Admiral Chester Nimitz advance warning of Japan’s plan of attack, the U.S. fleet benefited from another key technological advance at Midway: radar. The U.S. Naval Research Laboratory (NRL) had developed the first radar system prototype by 1938, and early radar systems were placed aboard carriers and other ships leading up to the Pearl Harbor attack.

At Midway, all three U.S. carriers and some supporting vessels benefited from radar, which allowed them to detect approaching Japanese aircraft at long range and better prepare for their attacks. In contrast, the Japanese ships relied solely on human lookouts, allowing U.S. dive-bombers to remain undetected until virtually the moment they reached attack position.

Aircraft carriers made the difference—on both sides.

By chance, none of the three U.S. aircraft carriers in the fleet at the time were at Pearl Harbor on December 7, 1941; all were out to sea on maneuvers, and all escaped unscathed.

This failure would come back to haunt the Japanese in May 1942, when the first major carrier battle took place in the South Pacific. The Battle of the Coral Sea, in which Allied forces turned back Japan’s invasion of Port Moresby in New Guinea, was the first naval battle in history in which the ships involved never sighted or fired directly at each other.

The Battle of Midway confirmed the carrier’s emergence as the key naval vessel in World War II, displacing the battleship. Nimitz rushed three U.S carriers—the Enterprise and Hornet, which had participated in Col. James Doolittle’s raid on Tokyo in April 1942, and the Yorktown, which was damaged in the Coral Sea—to the central Pacific, laying a trap for the Japanese.

Meanwhile, Yamamoto’s two most modern carriers, the Shokaku and Zuikaku, had been damaged in the earlier battle, and were unavailable for use at Midway.

One U.S. carrier had undergone rush repairs just a week before the battle.

USS Yorktown, The Battle of Midway
Corbis/Getty Images
The aircraft carrier USS Yorktown is shown in dry dock at Pearl Harbor, as it is being readied for the Battle of Midway.

On May 27, 1942, the USS Yorktown struggled into Pearl Harbor, after traveling 3,000 miles across the Pacific. During the Battle of the Coral Sea, a 551-pound Japanese bomb had hit the Yorktown’s wooden flight deck, smashing through and exploding inside the ship. More than 1,400 repairmen worked around the clock, patching the holes in the Yorktown with steel plates, in order to have it ready for Nimitz at Midway.

After barely 48 hours in Drydock Number One at the Pearl Harbor Navy Yard, the Yorktown steamed out to join the Hornet and Enterprise 325 miles north of Midway, at a predetermined meeting spot known as “Point Luck.” The Yorktown’s presence caught Japan by surprise; they had thought they had disposed of the carrier in the Coral Sea.

Japanese counterattacks from bombers and submarines sank the Yorktown on June 7, 1942, but not before it managed to play a key role in the Allied victory at Midway.

In 1998, the Yorktown was finally located some 16,650 feet under the surface of the Pacific, by a team led by Robert Ballard, the undersea explorer known for discovering another famous wreck: the Titanic.

A celebrated Hollywood director shot footage of the battle.

The Battle of Midway
U.S. Navy/The LIFE Picture Collection/Getty Images
A film still shows a US Navy aircraft carrier, likely the USS Enterprise, during the Battle of Midway, from the John Ford-directed documentary 'The Battle of Midway,' 1942.

Best known for his masterful Westerns, and his longtime collaboration with John Wayne, director John Ford was also an officer in the U.S. Naval Reserve, and was tasked with making documentary films for the Navy during World War II.

At Admiral Nimitz’s request, the director was stationed on Midway during the battle, and suffered a “bomb concussion” and gunshot wound during the Japanese raid, according to now-declassified records. U.S. Marines gave Ford first aid, but he “did not leave his station until he had completed his photographic mission.”

Ford’s footage of the battle, and particularly the activities of U.S. B-17s (Flying Fortresses), appeared in The Battle of Midway, which won an Oscar for best documentary that year. Ford went on to lead the photographic unit for the Office of Strategic Services (OSS), the precursor to the CIA, for the remainder of the war.

The battle was a turning point—but maybe not for the reason you think.

Over the years, Midway has assumed near-mythic status as the moment fortunes shifted in World War II’s Pacific theater. Its impact has sometimes been attributed to the battle’s devastating impact on the Japanese strike force, which included the loss of four aircraft carriers, nearly 300 planes and as many as 3,000 men, including Japan’s most experienced pilots.

In fact, as historian Evan Mawdsley has pointed out, Japan’s fleet rebounded from the battle relatively quickly: Yamamoto retained his two most modern carriers, Shokaku and Zuikaku, and four smaller carriers that had not accompanied the Kido Butai carrier battle group to Midway. The United States also sustained damaging losses at Midway, and by the time of the Battle of the Santa Cruz Islands in October 1942, Japan was able to assemble a more powerful carrier fleet than the Americans.

Midway did, however, represent the point when the momentum shifted from the Japanese to the Americans in the Pacific. Japan’s Imperial Navy had failed to deliver its knockout blow, and U.S. war production was just ramping up, just as Yamamoto feared.

While Japan had no effective way to replace lost aircraft carriers as the war continued, U.S. shipyards began rolling out new carriers in 1943. It would be those vessels—along with the rest of the nation’s unprecedented wartime production—that would lead the American fleet to victory in the Pacific in 1945. 

HISTORY Vault: World War II

Stream World War II series and specials commercial-free in HISTORY Vault.