Submarines of the Imperial Japanese Navy
The ("I-15"-class) submarines (, , , , , , , , , , , , , , , , , , , ) were the most numerous type of submarines of the Imperial Japanese Navy during World War II. In total 20 were made, starting with "I-15", the class ship. These were fast, very long ranged, and carried a single Yokosuka E14Y seaplane, located in a hangar in front of the conning tower, launched by a catapult.
Japanese submarine tender Jingei
Under the Eight-eight fleet plan, the Imperial Japanese Navy planned to acquire 100 submarines for long-distance scouting operations, which would also be used to conduct attrition warfare against any enemy fleet approaching Japan. "Jingei" was intended to serve as a flagship for the Submarine Division Commander and as a depot ship for the nine submarines in a submarine division.