This class consisted of SENKO and MANKO MARUs, both completed in 1935 for Kinkai Yusen Kaisha. In 1939, Nippon Yusen Kaisha (NYK) acquired Kinkai Yusen Kaisha. SENKO and MANKO MARUs commercial service consisted mainly of transporting bananas and other fruits from Formosa to the Keihin area (Tokyo, Kawasaki and Yokohama) of Japan. Both ships were enlisted as auxiliary transports in the IJN: MANKO MARU in Aug '37 and SENKO MARU in Sep '41. MANKO MARU was sunk by an American submarine in Jul '44, N of Luzon. SENKO MARU was sunk postwar in Oct '45 off Sumatra by a Dutch air attack on Indonesian rebels.