|Died||from natural causes|
|Other names||Hirata Munisai|
|Notable students||Miyamoto Musashi|
Shinmen Munisai (新免 無二斎), also called Miyamoto Muninosuke, was a martial artist, expert in using the sword and the jutte. He was also the father of the samurai named Miyamoto Musashi. He was the son of Miyamoto Musashi no kami Yoshimoto, a vassal of Shinmen Iga no Kami, the lord of Takayama Castle in the Yoshino district of Mimasaka Province. Munisai was relied upon by Lord Shinmen Sokan, the head of the Shinmen clan and so was allowed to use the Shinmen name. He was one of the few to have obtained the title of "Unrivaled Under The Sun", title offered to him by the Shōgun Ashikaga.
Munisai founded his own ryūha: the Tōri Jitte Ryū, which was one of the schools taught to his son Miyamoto Musashi, who conceived the Hyōhō Niten Ichi-ryū.
Because of the uncertainty centering on Munisai (when he died, whether he was truly Musashi's father, etc.), Musashi's mother is known with even less confidence. Here are a few possibilities:
Sometime after Ashikaga Yoshiteru became the Shōgun, he started in Kyoto a comparison duel between Munisai, who was still called Hirata at the time, and the founder of the Yoshioka-ryū school of sword-fighting: Yoshioka Kenpo (who was also the sword instructor of the Ashikaga). Kenpo won the first match, while Munisai won the other two. This event later started a feud between Munisai's son Miyamoto Musashi and the following generation of the Yoshioka family. Munisai having won the match, the shōgun gave him the title of "Unrivaled Under The Sun".
Having heard about Munisai, the head of the Shinmen clan, Shinmen Sokan, recruited Munisai as instructor of his troops. In 1589, for unknown reasons, Sokan ordered Munisai to kill his student Honiden Gekinosuke. After this event, he started training his son Musashi in the ways of the sword and of the jutte, but it didn't last long since the inhabitants of Miyamoto village, displeased with Gekinosuke's death, forced him to move away in the village of Kawakami.