Genpei War: The Battle of Mizushima takes place off the Japanese coast, where Minamoto no Yoshinaka's invasion force is intercepted and defeated by the Taira clan.

The naval battle of Mizushima took place on 17 November 1183 during the Genpei War. One of the most important bases of the Taira was Yashima, a small island off the coast of Shikoku. In November 1183, Minamoto no Yoshinaka sent an army to cross the Inland Sea to Yashima, but they were caught by the Taira just offshore of Mizushima (水島), a small island of Bitchu Province, just off Honshū. The Taira tied their ships together and placed planks across them to form a flat fighting surface.

Minamoto no Yoshinaka , also known as Kiso Yoshinaka , was a Japanese samurai lord mentioned in the epic poem The Tale of the Heike. A member of the Minamoto clan, he was a cousin and later rival of shogun Minamoto no Yoritomo during the Genpei War between the Minamoto and the Taira clans in the late Heian period.

The Taira was one of the four most important clans that dominated Japanese politics during the Heian period of Japanese history – the others being the Minamoto, the Fujiwara, and the Tachibana. The clan is divided into four major groups, named after the emperors they descended from: Kanmu Heishi, Ninmyō Heishi, Montoku Heishi, and Kōkō Heishi, the most influential of which was the Kanmu Heishi line.

November 17 is the 321st day of the year in the Gregorian calendar; 44 days remain until the end of the year.