IJN subs were deployed for "fleet warfare", not merchant raiding. The costly job of sinking allied warships fell to the IJN sub fleet. It's estimated that IJN submarines sank less than 50 merchant ships during the war.
There were five midget Japanese submarines : I-16, I-18, I-20, I-22, and I-24 .
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This attack is known as the Attack on Sydney Harbor. During WWII, Japanese submarines attacked the Australian cities of Sydney and Newcastle.
The Imperial Japanese Navy started World War II with one of the largest submarine forces in the world. Despite the sinking during the war of several major U.S. warships by Japanese submarines, the Japanese were never able to effectively employ their submarines to any great extent. Japanese submarines tended to operate alone and were directed toward tactical gains. The United States, in contrast, employed wolf packs, embraced new technology, and engaged in a campaign of strategic submarine warfare. On Dec. 7, 1941, during the attack on Pearl Harbor, there where 3 Japanese submarines stationed in a picket line 100 miles forward of the carriers. They were the I-23, I-21, and I-19. There are even rumors of Japanese subs patrolling the East Coast during the war.
During World War 2, it is reported that over 2,000 variants of Japanese Submarines were used during World War 2. Out of this, it is estimated that 10,000s were likely to be used during WW2.
Submarines and aircraft carriers
Wolfpack was a naval strategy where a cluster of submarines would attack ships, just like a pack of wolves attacks their prey. In World War II, the German U-Boats used this tactic during the Battle of the Atlantic. The American submarines also did this against Japanese shipping. Anywhere between 3 and 34 submarines were used in convoys that involved the sinking of a ship. During the Iraqi War in 2003 the term Wolfpack referred to the American and British submarines working together to launch Tomahawk missiles against Iraqi targets.
German submarines, or "U-boats", did not CONTROL the shipping lanes, but they were able to intercept and sink a large number of cargo vessels sailing between North America and Europe.
Submarines were sometimes referred to as submersibles.
During WW2, all the major countries involved used submarines.
U-Boats, meaning "Under-sea boats" are German submarines originally built in 1904 for Russia during the Russo-Japanese War (1904-1905).
During WW2 the US Navy built 126 submarines.