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.
Japanese submarine I-22 (1938)
The boats were armed with eight internal bow torpedo tubes and carried a total of 20 torpedoes. They were also armed with a single /40 deck gun and two single or twin mounts for Type 96 anti-aircraft guns. They were equipped to carry one Type A midget submarine aft of the conning tower.
"I-22" was commissioned at Yokosuka, Japan on March 10, 1941. The submarine participated in the attack on Pearl Harbor, the Battle of the Coral Sea, and the attack on Sydney Harbour in May and June 1942. "I-22" disappeared while on patrol near Malaita in the Solomon Islands on or around October 4, 1942 and was presumed lost with all 100 hands.