Marion Franklin Tinsley (February 3, 1927 – April 3, 1995) is considered the greatest checkers player who ever lived. He was world champion from 1955–1958 and 1975–1991. Tinsley never lost a World Championship match, and lost only seven games (two of them to the Chinook computer program) in his entire 45-year career. He withdrew from championship play during the years 1958–1975, relinquishing the title during that time.
Tinsley retired from championship play in 1991. In August 1992, he defeated the Chinook computer program 4–2 (with 33 draws) in a match. Chinook had placed second at the U.S. Nationals in 1990, which usually qualifies one to compete for a national title. However, the American Checkers Federation and the English Draughts Association refused to allow a computer to play for the title. Unable to appeal their decision, Tinsley resigned his title as World Champion and immediately indicated his desire to play against Chinook. The unofficial yet highly publicized match was quickly organized, and was won by Tinsley.
In one game, Chinook, playing with white pieces, made a mistake on the tenth move. Tinsley remarked, "You're going to regret that." Chinook resigned after move 36, fully 26 moves later. The lead programmer Schaeffer looked back into the database and discovered that Tinsley picked the only strategy that could have defeated Chinook from that point and Tinsley was able to see the win 64 moves into the future.
The ACF and the EDA were placed in the awkward position of naming a new world champion, a title which would be worthless as long as Tinsley was alive. The ACF granted Tinsley the title of World Champion Emeritus as a solution.
In August 1994, a second match with Chinook was organized, but Tinsley withdrew after only six games (all draws) for health reasons. Don Lafferty, rated the number two player in the world at the time, replaced Tinsley and fought Chinook to a drawn match at game 20. Tinsley was diagnosed with pancreatic cancer a week later. Seven months later, he died.
He is sometimes listed as "Dr. Marion Tinsley." He had a doctorate from Ohio State in the mathematical discipline of combinatorial analysis. He worked as a professor of mathematics at Florida State University and Florida A&M University. Tinsley once claimed to have spent approximately ten thousand hours studying checkers while in graduate school. Tinsley also served as a lay preacher in the Disciples of Christ church.
World Championship titles
- 8 time world champion (Three-move): 1954, 1955, 1958, 1979, 1981, 1985, 1987, 1989
- 1 time world champion (Two-move): 1952
Tinsley died in Humble, Texas on April 3, 1995. He was 68 years old. He lived in Conyers, Georgia, but was visiting his sister in Texas when he died of cancer. He was survived by a twin sister, Mary Clark, who lives in Humble, Texas and by two brothers, Ed, of Sarasota, Fla., and Joe, of Thornville, Ohio. He is buried at Greenlawn Cemetery, Columbus, Ohio, next to his father, Edward H., who was buried on November 19, 1948 and his mother, Viola Mae, who was buried on June 1, 1987. His brother, Harold Edward is also buried there, and was buried on July 6, 2007.
- Jonathan Schaeffer. "Marion Tinsley: Human Perfection at Checkers?".
- "A Checkered Career". Sports Illustrated. Retrieved 8 December 2013.
-  Jonathan Schaeffer and Robert Lake. "Solving the Game of Checkers." Games of No Chance, vol. 29, 1996, p. 129-130.
- http://yellowmagpie.com/dr-marion-tinsley-draughts/: "Dr Marion Tinsley: The Checkers Mathematician", YellowMagpie
- 1994 Chinook-Tinsley checkers match
- "Marion F. Tinsley, 68, Unmatched As Checkers Champion, Is Dead". NNCheckers. Retrieved 9 December 2013.
- "Marion F. Tinsley, 68, Unmatched As Checkers Champion, Is Dead". NCCheckers. Retrieved 9 December 2013.
- University of Alberta article on Tinsley
- Marion Tinsley at the Mathematics Genealogy Project
- Marion Tinsley at Find a Grave