In the same year, Yoshimoto, who invaded Owari Province, was killed by Nobunaga ODA at the Battle of Okehazama, and therefore, he effectively inherited the family leadership and became the 10th head of the Imagawa family.
同年、尾張国に侵攻した義元が桶狭間の戦いで織田信長に討たれたため、実質的にも家督を相続して今川家の第10代当主となった。