Heiji Era

The Heiji period (1159–1160), though spanning less than one year, is an extremely important era in the developmental history of the Japanese sword. The Heiji Rebellion (the 12th month of Heiji 1; January 19 – February 5, 1160 in the Western calendar), which followed the Hōgen Rebellion, became the decisive phase of the power struggle between the Minamoto and Taira clans and also had a major impact on sword culture.

Establishment of the Blade Form

Swords from the Heiji period through the early Kamakura period were characterized by the "koshi-zori" (waist curvature), in which the curve is pronounced near the hilt. This form was regarded as easier to handle on horseback.

Technical Development

Blades that were more practical in combat and more durable came to be demanded, and the field moved toward the maturity of the kotō period.