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 I-15
I-15 was a Japanese B1 type submarine. She was completed at Kure Navy Yard on September 30, 1940, whereupon she entered into service with the Imperial Japanese Navy. Her first and only commanding officer was Commander Nobuo Ishikawa. "I-15" operated off the north coast of Oahu during the raid on Pearl Harbor. Her second wartime patrol, in May and June 1942, took her to the Aleutians, where she conducted reconnaissance of several islands. "I-15"s third and final patrol took place from August to November 1942, when she operated in the Solomon Islands in the South Pacific, supporting the Japanese efforts to hold Guadalcanal. One source (Morison) suggests that "I-15" hit the battleship with a torpedo on September 15, 1942. More recent authorities (Hackett & Kingsepp) maintain that the torpedo came from another submarine operating in the area, , which was also responsible for the sinking of , which "I-15" duly observed and reported. On November 10, 1942, a U.S. ex-destroyer (modified to a fast minesweeper), , sank "I-15" at Cape Recherche, San Cristóbal, with all hands lost.
Commander Ishikawa was promoted to the rank of Captain posthumously. On December 14, 1942, more than one month after "I-15" was sunk, sank an unknown submarine which it misidentified as the "I-15".