''Sunk: The Story of the Japanese Submarine Fleet, 1941–1945'' is a historic 1954 war memoir written by Mochitsura Hashimoto, a former Lieutenant Commander in the Imperial Japanese Navy. As one of only four surviving Japanese submarine captains from the war, Hashimoto provides a rare, firsthand perspective on the Pacific Theater, detailing the rapid technical and tactical collapse of Japan’s submarine force. He is best known for commanding the submarine I-58, which torpedoed and sank the USS Indianapolis on July 30, 1945—inflicting the greatest single at-sea loss of life in U.S. Navy history. Hashimoto recounts tracking and destroying the American heavy cruiser shortly after it secretly delivered atomic bomb components to Tinian. He describes the attack using traditional torpedoes and the aftermath of the event. The book is sharply critical of the Imperial Japanese Navy’s top brass. Hashimoto argues that leadership threw away crews and vessels through reckless strategy, terrible operational planning, and an outright neglect of scientific advancements. He covers the development and tragic deployment of Kaiten (suicide piloted torpedoes). He outlines how the submarine fleet essentially became a specialized kamikaze force, turning crews into "human ammunition". Hashimoto explains how a complete lack of modern radar and effective anti-submarine counter-measures left Japanese crews defenseless against escalating Allied technology.