Masato Yamaguchi, credited under the original name 山口正人, is a Japanese manga artist known for his work in the yakuza drama genre. His professional identity is primarily that of a manga creator and an original author for anime and film adaptations.

Yamaguchi is best known for the manga Shura ga Yuku, which was created in collaboration with writer Yu Kawabe. The manga was first published in 1991 in the magazine Manga Goraku by Nihon Bungeisha. This work serves as the foundational source material for subsequent adaptations.

The manga Shura ga Yuku was adapted into a two-episode original video animation (OVA) series. The OVA was produced by Toei Video and Knack Productions, with its first episode released on December 9, 1994, and the second on May 21, 1995. The story is set in the Kansai region and revolves around a fictional yakuza organization, focusing on themes of succession, betrayal, and conflict within the criminal underworld.

Beyond this specific work, no further details are available regarding Masato Yamaguchi's broader career, artistic identity, other original works, or industry significance.