Kawakami Gensai(河上 彦斎), 25 December 1834 – 13 January 1872) was a Japanese samurai of the late Edo period. A highly skilled swordsman, he was one of the four most notable assassins of the Bakumatsu period. Gensai's high-speed sword discipline was in the Shiranui-ryū, which is used as a loose historical basis for the Hiten Mitsurugi-ryū. Gensai himself also served as a loose basis for Kenshin.