Published in Japanese in 1949, Citadel in Spring is, at its heart, an autobiographical novel of the author's life from university through induction into the Imperial Japan Navy, assignment to intelligence service in China, and Japan's final defeat. In addition to details of actual code-breaking activities, it also paints grimly honest pictures of some of the fiercest naval battles of the war, and the horrors of the Hiroshima atomic bombing. As a witness to World War II and its effects on the people and culture of Japan, this document--although cast as fiction--is a crucial reminder of the real costs of war to a generation who have never experienced it.