This class consists of CHOJO, CHOAN and CHOKO MARUs, completed in 1927 for Osaka Shosen K.K. (OSK). They were later sold to Toa Kaiun K.K. CHOJO MARU was requisitioned by the IJA and served as Army transport No. 834. In Nov ’41, CHOAN and CHOKO MARUs were requisitioned by the IJN, converted to auxiliary gunboats in Dec ’41 and respectively renamed CHOAN MARU No. 2 GO and CHOKO MARU No. 2 GO. In Oct ’43, both were converted to auxiliary transports. All were torpedoed and sunk by American submarines between Jan and May ’44.