Kojirō Sasaki is a swordsman who is thought to have existed during the early Edo period. Not much is known about his true identity or history, an enigma with scholars to this day. In contemporary fiction, he is immortalized as Musashi's greatest rival. His final duel at Ganryūjima remains his most famous exploit. The Nobunaga no Yabou 201X poll for 4-star officers puts him in thirty-seventh place.