For the first time, two letters written by Japanese Adm. Isoroku Yamamoto — the architect behind the Dec. 7, 1941, attack on Pearl Harbor — have been made public. Donated by the naval officer ...

Adm. Isoroku Yamamoto, Japan’s chief naval strategist during World War II, was a gambler who “won large sums on poker, bridge, shogi—Japanese chess—and the Japanese game of stones known as ...