Hikosan gongen chikai no sukedachi (A vow to serve with a sword at Mt. Hiko Shrine: 彦山権現誓助剣) is an example of an adauchi mono (revenge tale: 仇打ち物). Osono and Okiku were the daughters of Ichimisai, a fencing master assassinated by a wicked samurai named Kyôgoku no Takumi. Osono and Okiku, Ichimisai's daughters, vow to avenge their father's murder. Although Okiku is killed by Takumi, Osono continues with the vendetta. Here she is disguised as a komusô (mendicant priest: 虚無僧) as she carries a large sedge hat and a shakuhachi (wooden flute: 尺八). Osono is one of the more intriguing and challenging roles in the kabuki repertory, as she is both very accomplished in the martial arts and a charming housewife.
The four large characters immediately above Utaemon's head read isse ichidai (Once in a lifetime performance: 一世一代).
References: NKE, p. 165