Segata Sanshiro is a fictional character created by Sega to advertise the Sega Saturn in Japan between 1997 and 1998. He is a parody of Sugata Sanshiro, a legendary judo fighter from Akira Kurosawa's Sanshiro Sugata.
Sanshiro is a Judo master that tracks down and punishes those who do not play the Sega Saturn. His name sounds similar to the phrase "You must play the Sega Saturn!" (セガサターン、シロ! Sega Satān, shiro!?) as well as "Sega Saturn, White" (セガサターン、白 Sega Satān, Shiro?), a reference to the new white color version of the Japanese Sega Saturn which followed the original gray version.