6th Fleet (Imperial Japanese Navy)
Despite these advantages, IJN submarines achieved remarkably little during World War II primarily having in hindsight suffered from the antiquated strategy of the Imperial Japanese Navy General Staff, who viewed submarines as little more than scouts whose main role was to locate and shadow enemy naval task forces in preparation for a decisive surface conflict. Maybe the IJN General Staff was slow to change as the submarines were generally slow to dive, easy to track with radar and sonar, difficult to maneuver underwater, and less sturdy than their German U-boat counterparts.
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.