Segata Sanshiro (Japanese: せがた三四郎, Hepburn: Segata Sanshirō) is a character created by Sega to advertise the Sega Saturn in Japan between 1997 and 1998. He is a parody of Sugata Sanshirō, a legendary judo fighter from Akira Kurosawa's 1943 film Sanshiro Sugata. In television and radio advertisements, Segata Sanshiro is portrayed by actor Hiroshi Fujioka. He was positioned as a martial artist who commanded people to play Sega Saturn games.
The advertising campaign began in 1997, with the Saturn having a modest level of success in Japan at that point. Fujioka was impressed by Sega's ideas for the character and felt that Segata Sanshiro would send a strong message to children. Advertisements continued both on television and on radio until 1999. As a result of the advertisements, Segata Sanshiro's theme song became a CD single and he was made the main character of his own video game, Segata Sanshirō Shinken Yūgi.
Segata Sanshiro has also had cameo appearances in video games, a comic book and a live concert. He has retained a cult following in Japan and has been credited with helping improve Saturn sales there. Western journalists have praised the appeal and advertising prowess of the character.