The conception took place in 1934. This was preceded by the solution of various technical difficulties in submarine construction, which could be completed in Japan in 1930. On the basis of this know-how, two test boats were built in 1934 in the Kure naval shipyard under the strictest of secrecy and were completed in the same year. They were given the designations No. 1 and No. 2 . This was followed by extensive sea trials. However, no more submarines of this type were built. On the basis of the experience gained, the test boat type A was designed in 1936 and the type A class derived from it in 1938 .
literature
Harald Fock: Naval small weapons. Manned torpedoes, small submarines, small speedboats, explosives yesterday - today - tomorrow. Nikol, Hamburg 1996, ISBN 3-930656-34-5 , p. 40.
