Shadow Conspirator(1982)

One night, Genjiro Tsurumi, a former ronin comes across a man being attacked by a group of assassins. The dying man is an official secret agent carrying a secret letter addressed to General Matsudaira. Genjiro meets with Matsudaira, who informs him of the existence of a mysterious group, the Hachitake... who aims to overthrow the Shogunate.