Sanshiro Segata is a fictional character created by SEGA to advertise the Sega Saturn in Japan between 1997 and 1998. Sanshiro is a Judo master that
tracks down and punishes those who do not play the Sega Saturn. His name sounds similar to phrase "Sega Saturn shiro!" meaning roughly "Do (Shiro) Sega Saturn!" (You must play Sega Saturn!) as well as "Sega Saturn White(Shiro)!", a reference to the new white color version of the Japanese Sega Saturn which followed the original gray version.
Sanshiro lives as a hermit high on a mountain,
devoting his life to intensive Sega Saturn training. He trains physically every day by carrying around a giant Sega Saturn on his back and punching buttons on its giant controller, as well as mentally by breaking piles of bricks with his head. He also frequently visits the city to seek out people who are not playing the Sega Saturn, and harshly teaches them a lesson. Sanshiro is a serious man with a firm sense of duty, who believes that playing video games is one of the most treasured activities in life.
The character became very well known in Japan, and helped make the Saturn successful in that country. When the Saturn was phased out and the Sega Dreamcast released, Sanshiro's end comes in the form of a commercial involving a missile directed at the Tokyo headquarters of SEGA. Sanshiro heroically jumps off the roof of the building, onto the missile, deflecting it into the atmosphere while riding it, in which he lives his last few moments chanting out "Sega Saturn Shiro!!" for one last time, and is killed in the subsequent explosion. The voiceover narrates that "Segata Sanshiro will live on in your hearts."
-courtesy of Wikipedia (becuase I am way too sick to try writing at this time)
A brief history of Segata Sanshiro in video (including tv spots)-]http://www.youtube.com/watch?v=o3lCF8O2N50