What Was the Kido Butai?

Despite its fierce-sounding name, Kido Butai only means “mobile force” in Japanese, better known as the 1st Air Fleet. Used as an organizational name, Kido Butai was Japan’s elite carrier strike force. This powerful group was established in 1941, just before Japan entered World War II. Centered on aircraft carriers, the group included battleships, cruisers, destroyers, and other support ships. Only the best personnel served in the Kido Butai. This powerful group gave Japan a formidable striking force early in World War II.

International naval limitation treaties between 1922 and 1936 limited Japan’s navy to sixty percent of the U.S. and Britain’s navies. Many ships could not exceed fixed tonnage limits. Japan felt the signers should have equal footing. Japan abandoned the treaties and set out to overcome any naval disadvantages.

Revamp and Revolutionize

Japan began to build carriers ambitiously in the 1930s; by 1939, it possessed six modern carriers. The Japanese Navy also built a small officer core that understood carrier operations and this group won the battleships versus airpower argument. This core gathered or trained others, many being China War veterans, to high standards. Japan understood what carrier planes could do – strike at long distances unexpectedly. Therefore, Japan developed outstanding planes like the Mitsubishi Zero fighter and the Nakajima Kate torpedo bombers. Most naval planes were a generation behind these in terms of performance and technology.

The Offensive Edge

The next dilemma was doctrine. The Japanese Navy realized that grouping their carriers forged a combined airborne strike force not seen prior. Carriers previously operated alone or in twos. Six modern carriers combined with their squadrons meant hundreds of planes could be brought to bear. Think of a naval Blitzkrieg; it became dogma, giving Japan a distinct advantage. In April 1941, this Fleet was organized as the First Air Fleet. 

Early Successes

Imperial Japan entered World War II with the December 8th attacks on Pearl Harbor and other Asian countries. The First Air Fleet hit Pearl Harbor, as the U.S. Navy was deemed the biggest Pacific threat. The pilots and crews explicitly trained for this attack, using mockups of the American base. Some three hundred sixty planes in two waves sank four battleships but did not find the crucial American carriers.

Starting in 1942, the Fleet sailed across the Pacific and beyond. These raids included strikes on British targets in the Indian Ocean, Australia, and New Guinea. Operations supporting the Army took place in New Guinea and the Solomon Islands. The Fleet suffered few losses due to their skill and weaker opponents.

The first real contest for Japan’s mighty carrier force came in May 1942 during the Battle of the Coral Sea, the first carrier-only battle. The Japanese sought to cut American communications with Australia and invade New Guinea. The Coral Sea was the keystone for these operations. The U.S. knew this couldn’t be allowed. Task Force 17, with carriers Lexington and Yorktown, sailed in. The First Air Fleet committed the two big carriers, Zuikaku and Shokaku.

In a first-of-its-kind battle, only the highly trained aircrews clashed – no ships, and the U.S. routed the Japanese. The Lexington was sunk, and Yorktown damaged. The U.S. Navy damaged the Shokaku and decimated Japanese aircrews. Neither Fleet carrier would be available for the next Yamato planned operation.

The Massive Gamble

The Kido Butai’s biggest gamble came at the June 1942 Battle of Midway. Yamamoto hoped to occupy Midway Atoll for future attacks against Pearl Harbor, pressuring America to negotiate to end the war. Preparations were made in complete secrecy. However, the U.S. Navy long cracked Japan’s encrypted radio codes and prepared a response. Japan’s Combined Fleet, led by the First Air Fleet, sailed in late May. The U.S. Navy positioned itself northwest of Midway waiting. Japan struck first, bombing Midway, but intense aerial battles soon started. American dive bombers caught the First Air Fleet exposed, its Zero fighters decimating U.S. Navy torpedo bombers. Bombs sank all four carriers and, with them, hundreds of veteran aviators and naval crew.

A Brutal Aftermath

Midway was Kido Butai’s swansong. The loss of four fleet carriers, hundreds of irreplaceable specialist aircrews, and sailors crippled the First Air Fleet. As the war revved up, a downward spiral ensued. Crews received half the previous training. Japan struggled to replace the lost carriers in a futile attritional war. The Kido Butai proved to be unstoppable for six months. In the naval battlegrounds of the early war, these exceptional crews and airmen were unparalleled. This proved to be their Achilles’ heel; no conditions existed where their skills could be re-created.