The Battle of Mizushima was a significant naval confrontation during the Genpei War, a conflict between the Minamoto and Taira clans for dominance in Japan. Minamoto no Yoshinaka, one of the Minamoto leaders, launched an invasion to expand his territory and eliminate the threat posed by the Taira clan. In November, Yoshinaka's forces sailed to the coast of Mizushima, anticipating an advantageous attack. However, upon arrival, they encountered the Taira clan's naval forces. A fierce battle ensued on the open waters, where the Taira's superior naval tactics and experience played a crucial role in their defense.

During the conflict, the Minamoto forces faced unexpected challenges with their ships and the terrain. The Taira clan, known for their formidable naval power, effectively countered the Minamoto's advances, leading to a decisive victory for them. This battle was characterized by fierce combat, demonstrating the effectiveness of Taira's naval strategies and the importance of control over waterways during the war. The outcome impeded Yoshinaka's campaign significantly, forcing him to retreat.

The defeat at Mizushima not only stunted Yoshinaka's invasion ambitions but also showcased the critical role that naval power played in the political struggles of the time. It highlighted the ongoing rivalry between these two powerful clans, shaping the tactics they would employ in future confrontations throughout the conflict.