Aircraft History
This seaplane was designed to be stowed disassembled aboard I-400 class submarine in a watertight cargo tube. Able to be assembled in approximately seven minutes, it was launched by a deck catapult for offensive bombing mission, and retrieved if desired.

Wartime History
This M6A1 was the last airframe built (serial number 28). Allied forces discovered at the Aichi factory.

War Prize Transported to USA
The aircraft was shipped to United States, then periodically displayed at Naval Air Station Alameda, California, until the U. S. Navy transferred the aircraft to the NASM Paul E. Garber Facility. It arrived in November 1962 but remained outdoors, in storage, for 12 years until in-door display/storage space became available. It is the only Seiran in existence in the world.

Restoration
Restoration work began on the floatplane in June 1989 and ended in February 2000, thanks to the outstanding work of a team of staff experts, many volunteers, and several Japanese nationals working at Garber and in Japan, spearheaded by Robert Mikesh.

No production drawings survive and the team conducted exhaustive researches into how various aircraft systems operated in order accurately reconstruct a number of missing components.

The aircraft revealed the difficult working conditions that plagued the Japanese aviation industry at the end of the war. Quality and workmanship were seriously lacking because of extensive damage to equipment and factories and the lack of skilled, professional workers (many were high school students).

A metal flap bore damage-probably the result of a bombing raid-hastily covered with fabric patches. They found the interior of fuel tanks contaminated with paper documents. Basic fit and alignment of parts was also poor in many places. Technicians found graffiti in various areas on the airframe. Someone, possibly a Japanese student, scratched a complete English alphabet inside one wing panel. Craftsmen were surprised to find no evidence that the pilot could jettison the floats in flight, contrary to claims by the designer. Aichi may have deleted this feature near the end of the M6A1 production run.

Display
After restoration, it was moved for public display to the NASM Udvar-Hazy Center in 2004, where it remains today.

References
The definitive account of the I-400 and its Seiran crews are told in the book I-400: Japan's Secret Aircraft-Carrying Strike Submarine: Objective Panama Canal. Air & Space Magazine "All and Nothing" covers the Seiran and I-400 November 2001 Issue, pages 22 - 31
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