Tinsley once remarked that he had become bored playing humans; there wasn't any challenge left. When he was young, Tinsley began to acquire the reputation of being unbeatable. For 45 years, most of his opponents would play for the draw; going for a win was unthinkable. Tinsley's enjoyment for the game waned, and at one point he retired from the game for 12 years because of a lack of competition. When the checkers program Chinook came on the scene, Tinsley relished the opportunity to play it. Chinook had no respect for Tinsley's abilities, willingly taking risks; anything to increase the chances of winning. Tinsley said that playing Chinook made him feel like a young man again. In 1990, Chinook earned the right to play Tinsley for the (human) World Checkers Championship. The ACF and EDA, the governing bodies for international checkers, refused to sanction the Chinook-Tinsley match, retroactively deciding that computers were ineligible for the World Championship. Tinsley was unable to change their decision and he took what he perceived as his only option. In 1992, he resigned as World Champion, and then immediately turned around and signed a contract to play the match with Chinook. Although this match was not the "official" World Championship, Tinsley was the champion and Chinook the official challenger. In their embarrassment, the ACF and EDA hastily created a new "Man-Machine" World Championship title so they could be part of the Chinook-Tinsley match. The ACF and EDA were now faced with the prospect of crowning a new human World Champion, which was meaningless as long as Tinsley was alive. They decided to award the title World Champion Emeritus to Tinsley to ensure he was always the Champion. The match was held in London in August 1992 with Silicon Graphics sponsoring the event. The final result was four wins for Tinsley, two for Chinook and 33 draws. Chinook's two wins represented only the 6th and 7th losses by Tinsley since 1950. In August 1994, Tinsley battled Chinook again for the Man-Machine title. After 6 games, all draws, Tinsley resigned the match and the title to Chinook citing health reasons. A week later, Tinsley was diagnosed with cancer and 7 months later he succumbed to the disease.
In the domain of competitive mind games, such as chess or bridge, Tinsley's record is unparalleled. Strong players come to the fore frequently, but their tenure at the top is limited. In chess, Emmanuel Lasker was World Champion for over 20 years, but this is an isolated exception. Being the best over a 45 year period is unprecedented. Was the Tinsley of 1994 a weaker player than, say, the Tinsley of 1950 or 1970? Knowledgeable checker players claim that the Tinsley of 1994 was as good as he had always been. However, in old age he became lazy, winning the minimum number of games needed to win a tournament or match, and then effortlessly drawing the rest (even not bothering to win won positions because it required too much effort).
What made Tinsley such a strong player? I asked him that question several times, without getting an adequate answer. Like many strong game players, Tinsley says that when playing a game he just "knows" the right move to make. The solution to a problem was immediately obvious to him, even without having analyzed all the ramifications of the move. He was rarely wrong.
Having observed him for several years, I can make a few comments on his strength. First, there is no doubt that Tinsley had an incredible memory. Before I had ever met the man, people told me apocryphal stories. One man claimed that when Tinsley was young, he studied checkers 8 hours a day, 5 days a week. As he got older, Tinsley studied only one day a week. This person claimed that Tinsley could recall every one of those sessions. Needless to say, I found this difficult to believe. After Chinook's first game against Tinsley in 1990, we started analyzing the game. Tinsley began recounting the history of the line we played, recalling games he played in the 1940's! The move sequences flowed easily from him without hesitation, sometimes annotated with the name of the opponent, date or place where the game was played! 1947 was as vivid in his memory as if it were only yesterday. The second facet to his play was his incredible sixth sense. A glance at a position was sufficient to tell Tinsley everything he needed to know. For example, in 1990 Chinook was playing Tinsley the 10th game of a 14 game match (won by Tinsley 1-0 with 13 draws). I reached out to play Chinook's 10th move. I no sooner released the piece when Tinsley looked up in surprise and said "You're going to regret that". Being inexperienced in the ways of the great Tinsley, I sat there silently thinking "What do you know? My program is searching 20 moves deep and says it has an advantage". Several moves later, Chinook's assessment dropped to equality. A few moves later, it said Tinsley was better. Later Chinook said it was in trouble. Finally, things became so bad we resigned. In his notes to the game, Tinsley revealed that he had seen to the end of the game and knew he was going to win on move 11, one move after our mistake. Chinook needed to look ahead 60 moves to know that its 10th move was a loser. In my experience with tournament chess and checker players, the sixth sense is experience. It is well-known how intensely Tinsley studied the game, analyzing anything from a Grandmaster game to a game between novices. His uncanny ability to know good from bad and safe from dangerous, is the direct result of all his hard work. Strong chess players have the same ability, but perhaps it is not quite as evident as it was with Tinsley.
What made Tinsley special was his play away from the board. He was universally liked. He was kind and gentle, eager to talk equally with checker master and checker novice. The first time I met him is forever indelibly imprinted on my mind. I was attending Chinook's first checker tournament in 1990. I had never attended such an event before and knew no one. I walked in the door, looked around for someone in authority. Not being familiar with anyone, I must have looked lost. This tall slim man walked up to me and said "You look like a checker player. Can I help you?" He proceeded to introduce me to the tournament organizer and director, and enquired as to whether we needed any help with the hotel. This kind stranger turned out to be Marion Tinsley. I was a stranger walking in off the street and was treated royally by the World Champion. Even though Tinsley was our adversary over the checker board, away from it he was our friend. Professionally, Tinsley was professor of Mathematics at the University of Florida at Tallahassee. Away from work and the checkers board, Tinsley was a Baptist minister. Tinsley could have said "no" when faced with the prospect of defending his title against a computer. Instead he bravely said "yes", setting a precedent that we hope will serve as an example to champions in other competitive games. It was Tinsley's fervent wish that he remain an undefeated champion. As long as his health remained sound, he claimed he would never lose a match to Chinook or anyone else. It was the Chinook team's wish to defeat Tinsley and become the first computer World Champion (in any game). In the end, both sides got their wish. Chinook reluctantly became the first computer World Champion by winning on forfeit from Tinsley. Tinsley, however, remained undefeated over-the-board. The exception was in Tinsley's final tournament. In the 1994 U.S. Championship, Tinsley tied for first place with Chinook and Don Lafferty.
Tinsley actually resigned his title in 1991, pre-empting the Oldbury v Hallett match, Ed.