Kumagai no Jirō Naozane was a famous soldier who served the Genji Clan during the Heian period of Japanese history. Kumagai is particularly known for his exploits during the Genpei War, specifically for killing the young warrior Taira no Atsumori at the battle of Ichi-no-tani in 1184. Atsumori's death and the circumstances surrounding it went on to be fictionalized and retold in numerous forms, including the Heike Monogatari epic, a number of Noh plays, and in the jōruri and kabuki theatres as well.