Several Japanese warships under construction since 1937

A letter of the German naval attache in Japan dated Tokyo, Japan 17 July 1938 referred to the press reporting that in 1937 was started with building for the Japanese of the submarine U-16 at the navy yard at Kure, the minesweepers No. 9 at the navy yard at Maizuru and No. 10 at Ishikawajima Zosenjo and the submarine chasers No. 4 at Osaka Tekkojo , No. 5 at Yokohama Dock Mitsubishi Jokogyo, No. 8 at Tama Zosenjo, Mitsui and the No. 11 at Tsurumi Seitetsu Zosenjo.

Source

High Command of the Kriegsmarine (OKM). Case 36