Natsushio-class submarine
 The Natsushio-class submarines were significantly smaller than the next generation Japanese submarines the Ōshio and the Natsushio-class submarines were the development of the Hayashio-class submarines. Also Natsushio-class is one of the (coast-defence) hunter-killer submarine (SSK) of JMSDF. Construction of the two subs in the class was approved under the First Defense Buildup Program 1958-1960. However the MSDF brass did not welcome the small submarines.