The Washington Naval Treaty of 1922 allowed Japan to build three large battleships to every five built by Britain or the United States. This was more than either Italy and France but the Japanese Navy was unhappy with the agreement and was determined to compensate for these low numbers by producing the world's most powerful fighting ships.
By 1941 Japan had the third largest navy in the world, after the US Navy and the Royal Navy. However in the field of naval aviation it was considered to be the best in the world. It had ten large aircraft carriers with specially built aircraft and highly trained crews.
The Japanese Navy also had 12 battleships, 100 destroyers, 18 heavy cruisers and 18 light cruisers. Most destroyers and cruisers were fitted with the 24-inch Long Lance torpedo. This oxygen-powered weapon could deliver a 1,000lb warhead at 49 knots over almost 11 miles.
At the outbreak of the Second World War the Japanese Navy was disadvantaged by not possessing operational radar. Other problems included the breaking of the Japanese codes by the US Navy and the dependence on imported oil.
Although the Japanese Navy backed up by the Japanese Air Force won a great victory at Pearl Harbor, it suffered a crushing defeat at Midway in June 1942. A lack of raw materials meant the shipyards were unable to replace the ships being sunk and outnumbered by the US Navy active submarine operations virtually came to an end in 1944.
Leyte Gulf was the the largest naval engagement in history. It was a decisive victory for the Allies with the Japanese Navy losing four carriers, three battleships and ten cruisers. This comprehensive defeat virtually ended Japanese sea power.
The last serious action took place off Okinawa when a 700 plane kamikaze raid on 6th April, 1945, sunk and damaged 13 US destroyers. The giant battleship, Yamato, lacking sufficient fuel for a return journey, was also sent out on a suicide mission and was sunk on 7th May.