Submarines of the Imperial Japanese Navy
The Imperial Japanese Navy's doctrine of fleet warfare ("guerre d'escadre") resulted in its submarines seldom posing a threat to allied merchant convoys and shipping lanes to the degree that the Kriegsmarine's U-boats did as they pursued commerce raiding against Allied and neutral merchant ships. During the war, IJN submarines did sink about 1 million tons (GRT) of merchant shipping (184 ships) in the Pacific; by contrast U.S. Navy submarines sank 5.2 million tons (1,314 ships) in the same period, while U-boats of Nazi Germany's "Kriegsmarine", the IJN's Axis partner, sank 14.3 million tons (2,840 ships) in the Atlantic and other oceans. During the last two years of the War in the Pacific, many IJN submarines were also occupied serving to transport supplies to isolated island garrisons, ones that had been deliberately bypassed by the Americans and the Australians and which could not be reached by surface transports because of blockade by Allied warplanes and naval vessels.
HA. 19 (Japanese Midget Submarine)
The HA. 19 (also known as Japanese Midget Submarine "C" by the US Navy) is a historic Imperial Japanese Navy midget submarine that was part of the Japanese attack on Pearl Harbor on 7 December 1941. This submarine was ordered to enter Pearl Harbor then attack the American warships with its torpedoes and then be scuttled with explosives next to a warship. However, she did not enter the harbor, and was grounded and captured. The submarine was eventually put on display near the submarine squadron at Naval Station Key West, Florida, then moved to the nearby Key West Lighthouse and Military Museum. "HA. 19" is now displayed at the National Museum of the Pacific War in Fredericksburg, Texas.