Japanese type-A midget sub salvaged near Pearl Harbor

By definition, a midget submarine is less than 150 tons, has a crew of no more than eight, has no on-board living accommodation, and operates in conjunction with a mother ship to provide the living accommodations and other support. The Japanese Navy built at least 800 midgets in 7 classes, but only a fraction had any noticeable impact on the war. Their intended purpose initially was to be deployed in front of enemy fleets, but their actual use would be in harbor attacks and coastal defense.

Japanese type-D sub sitting at the Yokosuka Naval Base, Sept. 1945

The Japanese midget subs were not named but were numbered with “Ha” numbers (e.g., Ha-19). These numbers were not displayed on the exterior and operationally the midgets were referred to according to the numbers of their mother ships. Thus, when I-24 launched Ha-19, the midget…