Go Bet   

The game of Go has very simple rules, but an enormous depth of possible strategy. Unlike Chess, the huge size of the 19x19 playing board makes brute-force search by computers to be not an effective strategy for playing the game at an advanced level. As of 2003, any reasonable human amateur can defeat the world's best Go programs, and human Go experts can just toy with the programs. For more background about Go, check the links on the Kiseido Go Server.

Update (Spring 2010): the best Go programs are now competing in the middle of the professional ranks. The breakthrough insight seems to have been to use Monte Carlo methods for training the learning systems.


On December 23, 2003, a lifetime man-vs-machine Go bet was entered into by Howard Scott Roy (on the side of the machines), vs. Will Harvey, Don Geddis, and Narinder Singh (on the side of the humans).

Every six months, for the rest of their lives, the four will gather in order to play a Go match between Scott's program (the machine) and Will (the human). The stake for each match is $30, at even odds.

For a summary of results, please check the main Go Bets page.


Scott, Will, Don, and Narinder all met in computer science graduate school at Stanford University. Scott became known for making arrogant intellectual claims, which he occasionally could not back up. (The rest of us interpreted this as a money-making opportunity.)

For example, on January 14, 1994, Scott made a bet with Ronny Kohavi that he could write a machine learning (automatic classification) program that surpassed the well-known state-of-the-art at the time (a program called C4.5). Don was one of the judges. Scott lost, essentially by default, although his program did just manage to start running.

Later, Scott spent a number of years proclaiming that he had an insight in how to write a Go-playing program, which he believed would make it the best such program in the world. After listening to this endless drivel, some pointed questions eventually revealed that he hadn't bothered to implement his program completely. And that, in fact, his insight was for only one phase of the game, whereas a real candidate program would of course need to play a full game of Go.

After suitable mocking, on December 2, 2002, Scott offered a bet: in six months, he would write a Go program that would defeat a human novice. Don Geddis, who had never played a game of Go, and didn't even know the full rules, was selected to represent the humans. Which could learn to play Go better over the same amount of time: a human, or Scott's program?

On Sunday, June 8, 2003, at 11:30am, the grand challenge took place at the Stanford Coffee House. The full results are available. Suffice it to say that Scott's program lost to Don. By a lot.

Undeterred and unrepentant, Scott offered to re-up for another six months. Don was exhausted from his (needless) preparing for the contest, but Will Harvey (a much better player than Don) offered to take his place to defend the humans. Scott was less excited, but changed his tune after Don and Will each offered him 100:1 odds on $10.

On Sunday, December 7, 2003, Will, Don, and Narinder all met for lunch at the Stanford Coffee House. Scott Roy did not appear. (He would claim to being in Chicago at that time.) Scott later admitted that he had only worked on his program for about three hours in the previous six months, and given that Don (a much weaker novice) had crushed the program then, it was a mere formality that Will would win. Scott conceded the $10 each to Don and Will without even playing the game.

Following this was much discussion about future bets. Scott was happy to keep renewing on the same terms. Will, Don, and Narinder were annoyed that Scott didn't show up, and also that he didn't work on the program. (The goal, of course, is for Scott to spend enormous energy on improving his program ... only to lose miserably anyway.) Scott was not willing to raise the stakes substantially, which the rest of us thought might increase his pain sufficiently to force him to actually work on the program.

We finally settled on the perpetual (lifetime) bet described on this web page.



Scott Roy's program

Will Harvey



Effective Date and Termination


Wager agreed to on December 23, 2003 by

Howard Scott Roy
Will Harvey
Don Geddis
Narinder Singh

Note: The sections below are for amusement only, and not part of the official Go Bet.

Extra Credit

For those interested in taking this a step too far, try to compute the expected (present) value of this bet. What would be a fair price for one of the bettors to buy their way out?

You'll need to figure out the expected lifespan of each person, and the chance that Scott will ever write a program that defeats Will. Also, don't forget to discount the value of money in the far future. This is significant, because it is likely that Scott will pay out for a (long?) time in the near future, but then may switch to receiving payment indefinitely (if at some point he does manage to write a program than can defeat Will).

Also don't neglect the idea that, if Will ever loses, he might choose to train and improve his own skills, thus raising the bar required by Scott's program.

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