The M6A was designed to be operated entirely from an I-400 class submarine and could be used either as a dive bomber or a torpedo bomber. The prototype first flew in November 1943 and the first production aircraft was completed in October 1944. The name ‘Seiran’ translates as ‘Clear Sky Storm’, but the type was never encountered in combat and did not get allocated an Allied reporting name. The first operational mission was to have been an attack on the Gatun Locks of the Panama Canal, to cut off the American supply route. Two submarines, the I-400 and I-401, sailed on 23rd July 1945 carrying six Serians between them, with the aircraft reportedly painted in US markings. The Japanese surrendered before the attack took place and the aircraft were destroyed to prevent capture. This is the only surviving example of the type and is the last of the 28 aircraft built. She was surrendered to American occupation forces in Yokosuka by Lt. Kazuo Akatsuka of the Imperial Japanese Navy, who flew the aircraft from Fukuyama. It was shipped to the United States and became one of a large number of aircraft stored for museum use, officially being handed over to the Smithsonian Institute in 1960. Restoration began in June 1989 but having previously spent many years outside she was in a poor state and the project was not completed until February 2000. She is seen on display in the Steven F. Udvar Hazy Center as part of the National Air and Space Museum. Washington Dulles International Airport, Chantilly, Virginia