The war between the Heike and Genji clans in the twelfth and thirteenth centuries is among the most compelling and significant moments in Japan's history, immortalized in The Tale of the Heike. Beyond the events recorded in this canonical text, the conflicts of the surrounding years are crucial to medieval Japanese culture and history. In 1156, power began to slip away from the court nobility in Kyoto. A shogunate was later founded in Kamakura,...