Koji Sato is the main antagonist of 1989 American film Black Rain. Sato is a cruel Yakuza leader who killed Charlie Vincent. He was portrayed by Yusaku Matsuda who died in 1989 after losing battle with bladder cancer.
Sato first appeared in the movie when he kills two pairs of Yakuza rivals. Before he was arrested by American cops Nick Conklin his partner and friend Charlie Vincent went to Osaka however Sato's henchmen impersonate police officers and take Sato off of the plane and stealing firearms and Nick and Charlie stay in Japan (whom they blamed for Sato's escape before senior police officer assigned them to Masahiro Matsumoto) and revealed that Sato planned gang war with his former boss Sugai, One night Charlie and Nick left the hotel when a punk who working with Sato harassed them and steeling Charlie's raincoat who followed them lead an underground parking garage but it was trap for him as Nick horrible watched in security gate when Charlie was beheaded by Sato and taunted him. After Nick team up with Matsumoto for revenge of his partner's death, Sato had meeting with Sugai after stolen money from New York, Joyce deal with Sugai (Who had grudge against Americans who bombed Hiroshima) eventually help Nick for bring Sato down after learning Sato planned Massacre. At meeting table both Sato and Sugai faced off when Sugai demand him to pay his sins by cutting one's finger but Sato refused his postie and stab Sugai before he escaped with bike and Nick chased him down where the gunfight between two gangs being and Nick manged beaten Sato for good for what did to Charlie. In the end Sato was handcuffed and faced his crimes.
- After Yusaku Matsuda was diagnosed with cancer and keep secret from film crew include the director and costars without knowing it and Matsuda refused chemotherapy, as he thought it would affect his ability to act in the film before passed away after five months the film was released.
- Ironically his son Ryuhei Matsuda would stars as Kenji Gato from The Raid whose father was rival of Uco's father.