This class consists of ROKKO and ASO MARUs. Both were completed in 1923 for the Nippon Yusen Kaisha (NYK) Line of Tokyo. In '37, both were chartered to the Imperial Army (IJA) and saw service in the Second Sino – Japanese War. Later, both were requisitioned by the IJA and served in the Pacific War.
In '44, ROKKO MARU was bombed and sunk by American aircraft off Formosa
while ASO MARU was torpedoed and sunk by an American submarine.
