On the early morning of December 7, 1941, the Imperial Japanese Navy launched an attack on the United States naval base at Pearl Harbor, Hawaii. A key but often overshadowed component of this assault were the Japanese mini submarines, part of a secret and ultimately ill-fated mission that has left a lasting legacy beneath the waves.
During the Pearl Harbor attack, Japan deployed five Type A kō-hyōteki midget submarines, each manned by a crew of two and carrying a payload of two torpedoes. These mini subs were tasked with infiltrating the harbor and targeting ships trying to escape in the chaos. The plan was bold; the submarines would enter under the cover of darkness, surface to fire their torpedoes during the aerial onslaught, then dive and escape, meeting with their mother submarines that evening.
Despite the meticulous planning and the devastating impact of the air attack, the mini submarines struggled to fulfill their objectives. Only one managed to enter the harbor, but was quickly detected and sunk. Another washed ashore the following day, and its surviving crew member, Kazuo Sakamaki, became the first Japanese prisoner of war. His captured sub was later toured across the U.S. to raise war bonds and now rests at the National Museum of the Pacific War in Fredericksburg, Texas.
The other three submarines met different fates. One attempted to follow a U.S. ship into Pearl Harbor but was engaged and destroyed by the USS Ward, marking the first American combat action of the Pacific War. The two remaining midgets were lost—until their later discovery revealed the final chapters of their story. In 1951 and 1960, both submarines were found in shallow waters off the entrance to Pearl Harbor; their wrecks provided invaluable historical insights before being treated with the respect due to war graves.
The rediscovery of these submarines not only adds poignant details to the record of December 7 but underscores the human cost of war. The wrecks are now considered historic sites and war graves. Managed by NOAA and the National Park Service under agreements with the Government of Japan, these sites are also protected by the Sunken Military Craft Act. This legislation, administered by the U.S. Navy’s Naval History and Heritage Command, ensures the sanctity of these final resting places, as well as their preservation as historical resources.
Relevant articles:
– Japanese Mini Submarines at Pearl Harbor, NOAA Office of National Marine Sanctuaries (.gov)
– The Midget Subs That Beat the Planes to Pearl Harbor, History.com, Dec 6, 2016
– Pearl Harbor: A Midget Sub in the Picture?, U.S. Naval Institute