Sato Toguchi was the uncle of Chozen and was the owner of Sato's karate. He had the biggest dojo in Okinawa.Sato is the enemy of Miyagi.
He was once Miyagi's best friend, as during their childhood, Miyagi and Sato had a strong brotherly friendship. Their friendship was so strong that Miyagi even asked his father to teach karate to him and Sato both (even though traditionally it had only been taught from father to son). However, when the two grew older, Sato had been arranged to marry a girl named Yukie. Although Yukie was arranged to marry Sato, she had instead fallen in love with Miyagi. Their love was so strong to one another, that Miyagi had announced that he would break the tradition of arranged marriage and marry Yukie anyway. Sato however, felt disgraced and challenged Miyagi to a fight to save his honor. But Miyagi left Okinawa the next day.
When Miyagi returned to Tome village with Daniel, Sato had become a rich industrialist and had been eager to face his old friend in a death match. However, the two became friends again when Miyagi saved his life during a typhoon, but his relationship with Chozen was now destroyed because Chozen had refused to aid Daniel in rescuing a young girl from the typhoon. Sato is not a villain per se, but however more along the lines of the tragic anti-hero who eventually finds redemption and peace. All of Sato's actions against Miyagi were out of anger of his former friend dishonoring him, though he does show signs of sympathy and respect by letting Miyagi and Daniel see Miyagi's father for the last time and honoring a lost bet between Daniel and Chozen. However, after Miyagi saves his life, Sato has a complete change of heart. He uses his resources to rebuild Tome Village after the typhoon, relinquishes the deed to the village, asks Miyagi for forgiveness (and receives it), and announces that the O-Bon Festival will resume.