sentences:  In 1938, he was assigned to the destroyer "Okikaze" on 15 December.Selected for submarine school the following year, Hashimoto was assigned to the Yokosuka Naval District on 20 May 1939 and enrolled in a six-month torpedo course on 1 June, subsequently entering the naval submarine school as a Class B student on 1 December.Upon completion of this training, he was assigned to the submarine "I-123 on 20 March 1940 as torpedo officer, transferring to the "I-155" on 15 October in the same role.