Junsen type submarine

The Junsen type submarines were divided into four classes: Four boats were built in 1923-1929.

Japan received six U-boats from Germany as reparations of World War I.

The IJN could not find an optimal design of fleet submarine, so they and Kawasaki Heavy Industries sent many technical officers to the United Kingdom and Germany and got drawings of advanced submarines.

She was built in 1931 under the 1st Naval Armaments Supplement Programme (Maru 1).

These boats combined the good points of the Junsen II and the Kaidai V. They were built in 1934 under the Maru 2 Programme.

I-1 in 1930
I-5 in 1932
I-6 in 1935
I-7 in 1937