No.1-class minelayer

The No.1 class auxiliary minelayer (第一号型敷設特務艇,) was a class of minelayers of the Imperial Japanese Navy (IJN), serving during World War II. They were built to supplement the timeworn Sokuten-class. 4 vessels were built in 1941–42 under the Maru Rin Programme (Ship # 257–260).

Background

 * In 1939, the Sokuten-class was the main minelayer of the local guard districts. However, they were too old. The IJN wanted new small minelayers for local guard districts.
 * In 1940, the IJN found out a handy boat. It was a standard longline fishing ship Sōyō Maru (160 tons) by the Ministry of Agriculture, Forestry. The IJN made a model of it and completed a design of new small minelayer. Uraga Dock Company built all of the vessels.