Samurai Assassin is a 1965 Japanese film directed by Kihachi Okamoto and starring Toshiro Mifune, Koshiro Matsumoto, Yūnosuke Itō, and Michiyo Aratama. It is set in 1860, immediately before the Meiji Restoration changed Japanese society forever by doing away with the castes in society and reducing the position of the samurai class.

Toshiro Mifune was a Japanese actor and producer. A winner of numerous awards and accolades over a lengthy career, Mifune is best known for starring in Akira Kurosawa's critically acclaimed jidaigeki films such as Rashomon (1950), Seven Samurai (1954), Throne of Blood (1957), The Hidden Fortress (1958) and Yojimbo (1961). He also portrayed Miyamoto Musashi in Hiroshi Inagaki's Samurai Trilogy (1954–1956), Lord Toranaga in the NBC television miniseries Shōgun, and Admiral Isoroku Yamamoto in three different films. He is widely considered one of the greatest actors of all time.