Shimushu-class escort ship
The Shimushu-class escort ships were a class of kaibōkan built for the Imperial Japanese Navy just prior to World War II. Four ships out of an initially planned 16 vessels were completed. The class was also referred to by internal Japanese documents as the "A-class" coastal defense vessel .
Shimushu in 1940
Kaibōkan or coastal defense ship was a type of naval ship used by the Imperial Japanese Navy during World War II for escort duty and coastal defense. The term escort ship was used by the United States Navy to describe this category of Japanese ships.
The Japanese Etorofu in May 1943.