In the period of the Minamoto clan and the Taira clan, and in the medieval period in Japan, fairness and graciousness were required in a battle, and the battle was done on a one-on-one basis.
源平の時代や中世日本における合戦では正々堂々潔さが求められ、一騎討ち（一騎懸け）が行われていた。