By 1934 the Imperial Japanese Navy had already laid down or planned most of the tonnage for major warships, allowed under the 1930 London Treaty. However, the admirals were not contented with these designs. They wanted more carriers. One way to provide for additional aircraft carriers above the total tonnage allowed by treaties was to build hulls ostensibly for other designs but which could be quickly converted to carriers. Two classes of such ships were laid down in late 1934. The Chitose of the Chitose and Chiyoda twins were first. Laid down as seaplane carriers, Chitose was laid down November 16, 1934.
One week later the first hull of the second such class was laid down. On December 3, 1934 Shoho was laid down at Yokosuka with Zuiho following in June 1935. Alleged to be submarine depot ships, these ships were designed for conversion into light aircraft carriers or fast fleet oilers. Shoho, then known as Tsurugisaki, was launched June 1, 1935 and actually served as a submarine depot ship in January 1939. However, in 1941 she was sent to the yard for conversion into a carrier. On January 26, 1942 Shoho was commissioned as the newest member of Japan’s now victorious carrier fleet. With a displacement of 11,262-tons (standard), 14,200-tons (deep), the Shoho was 606-feet long with a 350-foot hangar. Capable of 28-knots, she could carry 30 aircraft.
Shoho holds the distinction of being the first Japanese aircraft carrier lost during World War Two. She was involved in operations against New Guinea, which resulted in the Battle of the Coral Sea. On May 7, 1942 a strike from USS Yorktown CV-5 found Shoho and quickly sent her to the bottom with bombs and torpedoes. Her sinking was marked with the phrase "Scratch one flattop!" Neptun #1226 is the Shoho during her very brief carrier as a carrier from January to May 1942. The Neptun Shoho is available from Collectio Navalis.