Submarines of the Imperial Japanese Navy
Imperial Japanese Navy submarines originated with the purchase of five Holland type submarines from the United States in 1904. Japanese submarine forces progressively built up strength and expertise, becoming by the beginning of World War II one of the world's most varied and powerful submarine fleets.
Junsen type submarine
The was a ship class of submarines of the Imperial Japanese Navy (IJN). There were four submarine designs of the Junsen type: J1, a modified J1, J2 and the J3.