壇之浦之戰
The Battle of Dan-no-ura was preceded by an immense struggle between the imperial rulers of Japan, the Taira clan (also known as the Heike), who the Heikegani crabs are named after, and the Minamoto clan (Genji), who were fighting for control of the throne at the end of the 12th century in the Genpei War (1180–1185).