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Checkers Solved, Unbeatable Database Created

Posted by Zonk on Thu Jul 19, 2007 03:41 PM
from the does-that-mean-we-don't-need-to-play-anymore dept.
Classic Games (Games) Programming IT Technology
tgeller writes "My story on the Nature site announced that a team of computer scientists at the University of Alberta has solved checkers. From the game's 500 billion billion positions (5 * 10^20), 'Chinook' has determined which 100,000 billion (10^14) are needed for their proof, and run through all relevant decision trees. They've set up a site where you can see the proof, traverse the logic, and play their unbeatable automaton. '[Jonathan] Schaeffer notes that his research has implications beyond the checkers board. The same algorithms his team writes to solve games could be helpful in searching other databases, such as vast lists of biological information because, as he says, "At the core, they both reduce to the same fundamental problem: large, compressed data sets that have to be accessed quickly."'"
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  • Wow. (Score:5, Funny)

    by Anonymous Coward on Thursday July 19 2007, @03:44PM (#19919185)
    Wow. Reminds me of how awesome I thought I was when I was 7 years old and I solved Tic Tac Toe.

      • Re: (Score:3, Informative)

        by PCM2 (4486)
        According to the article, checkers has been "solved" to the extent that they've developed a mathematical proof showing that it's impossible to beat the checkers software the researchers wrote. Even if the human plays a "perfect" game against the computer, the result will be a draw.

        So, in answer to your first question, none. Checkers might be "solved," but the computer is not guaranteed to win. (It is, however, quite likely.)

        In answer to your second question, if both sides play perfect games then you'll alwa

  • The writing's been on the wall... (Score:3, Informative)

    by Eco-Mono (978899) on Thursday July 19 2007, @03:46PM (#19919207) Homepage
    ...ever since the swelling of Chess's "opening book" began. They randomise starting back-rank positions now in some tournaments, to stave off the eventual "book death" that has already conquered checkers.

    • Re:The writing's been on the wall... (Score:5, Interesting)

      by dprovine (140134) on Thursday July 19 2007, @04:23PM (#19919655)

      They randomise starting back-rank positions now in some tournaments, to stave off the eventual "book death" that has already conquered checkers.

      I made up my own variation with randomness that I call Schrödinger's Chess [rowan.edu].

      Let me know if you try it out.

    • Re: (Score:3, Informative)

      by eclectro (227083)
      For those that are interested, I think the parent is referring to Chess960 [wikipedia.org].

      • Re: (Score:3, Informative)

        by SnowZero (92219)
        Created/endorsed by chess genius and raving lunatic Bobby Fischer [newsfromrussia.com]: "I don't play the old chess. But obviously if I did, I would be the best."

    • They randomise starting back-rank positions now in some tournaments, to stave off the eventual "book death" that has already conquered checkers.
      Randomize or start with the pieces off the board? When I was still a member of the USCF in the 1970s, someone introduced a chess variant similar to that. Each side starts with 8 pawns on the 2nd on the board and the back rank empty. White still moves first, but the first 8 moves for each side must be to put the major pieces on the 1st rank. This eliminates the memorized opening book openings too and emphasizes chess middle game play which is what the game is about anyway IMO. This adds 16! different starting positions and maybe makes the game complex enough that it can never be solved deterministically in a useful amount of time, I hope so.

      I'm not surprised that checkers has been solved. As a programmer and an engineer, I cheer in the fact that a difficult problem has been solved, as a human being, I'm sad in a way. Computers are tools, humans are well, humans. There must remain some ways we can think better.

    • Re:The writing's been on the wall... (Score:5, Funny)

      by TED Vinson (576153) on Thursday July 19 2007, @10:24PM (#19922825)
      Good idea. Perhaps Checkers can be revitalized by randomizing which piece goes on which starting space too...

  • Slashdot effect. . . (Score:5, Funny)

    by ookabooka (731013) on Thursday July 19 2007, @03:48PM (#19919215)

    They've set up a site where you can see the proof, traverse the logic, and play their unbeatable automaton.


    Holy crap. . .you have any idea how badly their server is going to be slashdotted now? It's bad enough when its a php driven webpage but now you've just encouraged slashdotters to try a game or two against it. . .if the server crashes in the middle of a game is it considered a win for the human player?

    • Re: (Score:3, Insightful)

      by garcia (6573)
      Holy crap. . .you have any idea how badly their server is going to be slashdotted now? It's bad enough when its a php driven webpage but now you've just encouraged slashdotters to try a game or two against it. . .if the server crashes in the middle of a game is it considered a win for the human player?

      It's a little difficult to play when you can't even load the game...

  • It's a draw (Score:5, Informative)

    by elwinc (663074) on Thursday July 19 2007, @03:48PM (#19919221)
    The New York Times has the story too http://www.nytimes.com/2007/07/19/science/19cnd-ch eckers.html?ref=science: [nytimes.com]. They claim the best you can do is draw against chinook in deterministic checkers. The Times points out that:

    The new research proves that Chinook is invincible in the traditional game of checkers. But in most tournament play, a match starts with three moves chosen at random. In solving the traditional game, the researchers have also solved 21 of the 156 three-move openings, leaving a crack of hope for humans, at least for now.

  • Flawed proof (Score:5, Funny)

    by eln (21727) * on Thursday July 19 2007, @03:49PM (#19919237) Homepage
    Now, far be it from me to criticize the research of a group that can manage to convince someone to give them a grant to play checkers with a computer all day, but their "proof" on that site is a little suspect.

    When I click on the proof, all I get is a Java error saying "Unable to connect to server". While the inability to connect to the Checkers server may make it "Unbeatable" in a Wargames-esque "the only way to win is not to play" kind of way, it's kind of a cop-out.

  • We'll always have Go (Score:4, Informative)

    by roscivs (923777) on Thursday July 19 2007, @03:51PM (#19919259) Homepage
    Since Go [wikipedia.org] always comes up in these discussions, I'll take this opportunity to point those curious about the game to some places to learn more about it:

    http://playgo.to/interactive/ [playgo.to], learn how to play the game in an interactive fashion.

    http://361points.com/atarigo/ [361points.com], play "capture" Go against a simple computer opponent.

    http://www.gokgs.com/ [gokgs.com], after you've learned the rules, play against others online worldwide.

    http://www.godiscussions.com/ [godiscussions.com], have more questions about the game? Ask them on this discussion board devoted to the game.

  • Checkers, Not Draughts (Score:5, Interesting)

    by eldavojohn (898314) * <my/.username@@@gmail.com> on Thursday July 19 2007, @03:51PM (#19919261) Homepage Journal
    From the Wikipedia [wikipedia.org] entry:

    The most popular forms are international draughts, played on a 10×10 board, followed by English draughts, also called American checkers that is played on an 8×8 board, but there are many other variants. Draughts developed from alquerque.[2]
    Draughts would be a much much larger gamespace than Checkers. I noticed that draughts appeared in the tags of this story but it shouldn't.

    Also, I've heard before that "it takes longer to learn to play checkers at the master level than it does chess. What checkers lacks in breadth, it makes up in precision and finality. [smithsonianmagazine.com]" I realize that puts me at risk of being modded as flamebait but I wonder if any other Slashdot reader can confirm or contest that.

    • Re: (Score:3, Interesting)

      by tgeller (10260)
      Here's a relevant quote from Bob Newell (editor of The Checker Maven [bobnewell.net]) that didn't make it into the story:

      "[Checkers is] a very finely balanced game, and a very subtle game. The subtleties of checkers are not very well appreciated by the average player. You play as a kid and someone always wins. In chess, differences are larger: In chess, you can make a mistake and still recover. In checkers, if you make a mistake, even a small one, you probably won't recover. People are fascinated by this game of minutiae,

      • Re: (Score:3, Insightful)

        by pugugly (152978)
        I've never particularly seen that as an indication of 'subtlety' - Great, it's so subtle that you're allowed one mistake, then your done. By that definition, Tic Tac Toe is a deeply subtle game. Golly Gee.

        Or to put it differently, it's a game so subtle that one bad move will kill you, and tournament chess requires three moves at the beginning just to randomize it a bit.

        I guess I have a Chess bias - [Grin] Pug

    • Re:Checkers, Not Draughts (Score:4, Interesting)

      by mebollocks (798866) on Thursday July 19 2007, @04:55PM (#19920051) Homepage

      I will, therefore, take occasion to assert that the higher powers of the reflective intellect are more decidedly and more usefully tasked by the unostentatious game of draughts than by all the elaborate frivolity of chess. In this latter, where the pieces have different and bizarre motions, with various and variable values, what is only complex is mistaken (a not unusual error) for what is profound. The attention is here called powerfully into play. If it flag for an instant, an oversight is committed, resulting in injury or defeat. The possible moves being not only manifold but involute, the chances of such oversights are multiplied; and in nine cases out of ten it is the more concentrative rather than the more acute player who conquers. In draughts, on the contrary, where the moves are unique and have but little variation, the probabilities of inadvertence are diminished, and the mere attention being left comparatively what advantages are obtained by either party are obtained by superior acumen. To be less abstract --Let us suppose a game of draughts where the pieces are reduced to four kings, and where, of course, no oversight is to be expected. It is obvious that here the victory can be decided (the players being at all equal) only by some recherche movement, the result of some strong exertion of the intellect. Deprived of ordinary resources, the analyst throws himself into the spirit of his opponent, identifies himself therewith, and not unfrequently sees thus, at a glance, the sole methods (sometimes indeed absurdly simple ones) by which he may seduce into error or hurry into miscalculation.
      Edgar Allan Poe - The murders in the Rue Morgue.
      Great Story!

  • So, who wins? (Score:5, Interesting)

    by drfuchs (599179) on Thursday July 19 2007, @03:53PM (#19919293)
    Right. So, is it a win for the first or the second player? Would be nice to mention somewhere.

  • CmdrTaco = pwn3d (Score:4, Funny)

    by x.Draino.x (693782) on Thursday July 19 2007, @04:03PM (#19919421)
    http://games.cs.ualberta.ca/~chinook/cgi-bin/statu s.cgi [ualberta.ca]

    GAME 17:
    Opponent: Cmdr Taco (cmdrtaco@slashdot.org)
    Chinook color: White
    Level: Novice
    Move number: 3
    Game analysis: Chinook has a small advantage.

  • Chinook wind (Score:5, Insightful)

    by hey (83763) on Thursday July 19 2007, @04:23PM (#19919645) Journal
    For non-Albertans... a Chinook wind is some hot air the blows down the mountains and melts the winter snow for a week or so.
    http://en.wikipedia.org/wiki/Chinook_wind [wikipedia.org]
    So it an analogy for a bright new idea -- like a lite up light bulb.
    Therefore there are a zillion things called "Chinook" in Alberta.

  • Hmmmmm (Score:3, Funny)

    by TheOldSchooler (850678) on Thursday July 19 2007, @04:43PM (#19919905)
    So what happens if one automaton plays another? Does the universe implode in some kind of horrible checkers armageddon?

  • Kobayashi Maru (Score:5, Funny)

    by 3vi1 (544505) <evil_NO@SPAMhotmail.com> on Thursday July 19 2007, @04:49PM (#19919975) Homepage Journal
    The day an automaton is "unbeatable" is the day it's 500ft tall and shoots nuclear rockets from its fingertips. I think I know a relatively easy way to beat this checkers program.

  • Ok, for other english impared people wondering what is checkers, it is the US name for game of draughts [wikipedia.org]. If you follow that link, you'll instantly recognize the board [wikipedia.org] :)

    Of course, as a brazilian, I had no idea people played that on a 10x10 board around the world. Too bad they can't reuse the chess board :)

  • Gratuitous nostalga post (Score:4, Informative)

    by Joe Decker (3806) on Thursday July 19 2007, @05:37PM (#19920481) Homepage
    HAKMEM item 93 [inwap.com] is solved. Back in 1972 when HAKMEM was written, the AI Lab folks estimated a year or so of computer time then, I'm guessing, given how long has passed, that this was a bit optimistic.

  • Shaeffer's book about Chinook (Score:3, Interesting)

    by ferguson731 (547854) on Thursday July 19 2007, @07:15PM (#19921439)
    Jonathan Schaeffer 's book about the development of Chinook (from 1997):

    http://www.amazon.com/One-Jump-Ahead-Challenging-S upremacy/dp/0387949305 [amazon.com]

    Includes the details of the Tinsley matches and Tinsley's untimely death. Interesting for people interested in the effects of technology on human societies, as well as some of the technical aspects of the program (as it was in 1997).

    • So all we have to do to crash the eventual skynet is move in a direction that isn't diagonal? This is going to be easy.

      • Re: (Score:3, Insightful)

        by DavidShor (928926)
        The easiest way to keep "dumb" code from killing us is not to program them to do so. They could mutate their code and decide to kill us anyway, but at that point, they become "smart".

    • Re:Chess? (Score:5, Informative)

      by rustalot42684 (1055008) <rustalot42684.gmail@com> on Thursday July 19 2007, @03:52PM (#19919283)
      RTFA: 10^46.

      • Re:Chess? (Score:5, Informative)

        by NewsWatcher (450241) on Thursday July 19 2007, @10:53PM (#19922989)
        Oh yeah, not that complicated, until you consider that in the USA a billion is a thousand million, but in most of the world it is a million million. Or that a sextillion is derived from prefix "sex" which means six, (as in a sextet of ale) but is actually a one followed by 21 zeros.

        A septillion (from the word for seven) contains 24 zeros.

        So what you may ask is a one followed by 22 naughts? 10 sextillion. A one followed by 23 naughts? 100 sextillion. And yet instead of a one followed by 24 naughts being 1000 sextillion, it is all of a sudden a septillion, even though it has nothing whatsoever to do with the number seven.

        I don't even know why I care about all of this. I got to this thread late and the chances of anyone reading my post in the developers section of Slashdot are next to zero. Of course next to zero would be one and minus one. Oh gawd, don't get me started on that....

    • Re:Theoretical vs. practical (Score:5, Informative)

      by edremy (36408) on Thursday July 19 2007, @04:07PM (#19919471)
      No. Schaeffer has a book out ("One Jump Ahead") about writing Chinook. He thought the same when he started, but the project got rapidly far harder than he thought. It helped that the existing human champion (Marion Tinsley) was literally as close to perfection as any human has ever been at any game- they exhaustively studied every professional game he ever played and found something like a grand total of 10 actual mistakes in a 40 year career.

      It's a very sad book in many ways- there was a lot of tension between certain members of the team and you realized that professional checkers was dying rapidly. Tinsley and Schaffer set up a world championship rematch between them (Tinsely won the first one) and Tinsely pulled out after six games saying he felt ill. He checked himself into the hospital, was diagnosed with some aggressive form of cancer and died a few months later. Schaeffer basically retired Chinook from human tournaments since nobody else was even remotely close to Tinsley.

      It didn't make many headlines because everyone knows checkers is easy. Except that they are wrong- it's not.

    • Re: (Score:3, Informative)

      by Cervantes (612861)

      I've been developing an algorithm to solve that game for years, and so far all I've come up with is: start with the middle square.

      Nah, that's false.

      If you're going first, put your mark in the corner. Almost regardless of what your opponent does, put your next mark in an adjacent corner. He'll now have to block you, and then you put your third mark in yet another corner, and voila, you have 2 winning moves.
      The only defense against it is to take the middle square with your first move and then block whatever side X tries to take with your second, and then X has to block your row with his third. That ends the game in a draw.

      The only winn

    • Re: (Score:3, Insightful)

      by TaoPhoenix (980487)
      This type of proof is not the same as "your checkers set comes with a handheld database reader to show you the solution of the position you are in" - because it's NOT about 'average players making mistakes'.

      They went for the proof of the math behind the game. This article will also be a good flash answer against the wailers who say "but there are 500 billion billion *possible* positions in the game..."

      The answer: only a small portion of them *matter*.

      Here's the basic chain logic.

      "All endgames of 8 pieces or

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