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Rybka Solves the King's Gambit Chess Opening
New submitter smarq2 writes "Chessbase reports that chess programmer IM Vasik Rajlich has solved the King's Gambit chess opening with technical means. 3000 processor cores, running for over four months, exhaustively analyzed all lines that follow after 1.e4 e5 2.f4 exf4 and came to some extraordinary conclusions."
Update: 04/02 22:11 GMT by U L : Skuto points out that this is the same person who was found guilty of plagiarizing GNU Chess and Crafty.
There is only one move in which White can force a draw - and to find out what it is, you'll have to RTFA.
Nah, I'm just pulling your leg, here you go..
Anybody really interested in the details will still RTFA anyway and the rest of us won't be left hanging with a teaser.
"Whenever Rybka evaluates a position with a score of +/– 5.12 we don't need to search any further, we have our proof that in the continuation there is going to be a win or loss, and there is a forced mate somewhere deep down in the tree. We tested a random sampling of positions of varying levels of difficulty that were evaluated at above 5.12, and we never saw a solution fail. So it is safe to use this assumption generally in the search."
Hmmm... Really? The whole "solved" thing hinges on this assumption.
... so long as you still have a chance. The computers haven't reached professional level yet and certainly won't be able to compute the whole of the game in advance, even after a given opening, in the next decades.
You're right... that can't possible be that guy's wife. ;-)
They didn't calculate all possible moves, but skipped every branch where analysation showed an advantage high enough for one party to be "absolutely sure" to win. So while the algorithm is very sophisticated, it technically didn't solve King's Gambit.
Rybka was stripped of its world computer chess championship after it was found that the author plagiarized the chess engines fruit (free software, GPL, the current base of GNUchess) and crafty (opensource). Even so, chessbase keeps selling this stolen engine.
Slashdot ought to be ashamed to give publicity to cheats and thieves.
Can I still move the horsie?
Chess programs usually score a position in "pawn equivalents". Having one pawn more is a +1, unless your opponent has compensation in position. Having one less would be a -1. Other examples are:
-a knight or bishop is worth roughly 3 points
-a rook is worth roughly 5 points
In practice, skilled players will win a +5 position reliably. A +3 is usually enough as well. So even if Rybka's evaluation is a bit off, I would not see much chances to win the match from the inferior position.
C - the footgun of programming languages
Right on the surface, the King's Gambit doesn't look like a very good idea for white, throwing away a well-placed pawn on your second move. Apparently this was considered a good idea for a long time, though I (a mediocre-at-best player) don't see how it could work.
As white, the only advice you need from this study is "Don't do it." As black, the advice appears to be "Take the pawn if offered. The best they can do at that point is a draw, and if they differ from that line at all, they lose."
Assuming you're a great player, of course. I'm sure that I'd still get massacred if a real player were to play the King's Gambit against me.
First, the King's Gambit has not technically been "solved", for the most rigorous definition of "solved". Unlike, say, checkers, there are still lines (i.e. series of moves) within the King's Gambit that have not formally been examined.
Second, we are strictly speaking about the King's Gambit Accepted. That is, white begins with e4 (King's pawn forward two spaces), black replies classically with e5 (King's pawn up two spaces), white then gambits the f-pawn (King's bishop's pawn up two spaces), and black captures the f-pawn, accepting the gambit. As TFA mentions, the King's Gambit Declined has not been examined nearly as thoroughly.
Third, all of this is only somewhat relevant to actual chess playing, and only at the very highest levels of play; the average FIDE Master (i.e. a well above average tournament player, though nowhere near being among the 1,000 best players in the world) need not remove the King's Gambit from his repertoire because it has been "solved". This has, historically, been one of the most dynamic openings in chess, with tons of opportunities for tactical tomfoolery and psychological pressure. When we talk about "perfect play", or "near perfect play", we're already reaching beyond the level of world champions.
Fourth, while not every line has been thoroughly analysed, the ones that haven't are irrelevant. An advantage, in chess, is calculated on the basis of a difference of pawns. So, if the black player has all the same pieces as his opponent, save for an extra pawn, all other things being equal, we evaluate the position as -1 (i.e. from the perspective of white, the position is minus one pawn). Pieces other than pawns are weighed differently, even when we are solely looking at material differences. Traditionally, knights/bishops are said to be worth three pawns, rooks are worth five pawns, and the queen is worth nine pawns. However, the actual position of the pieces affects their worth; a knight very near the centre of the board is, often, worth more than a rook (i.e. A knight near the centre can have up to eight possible moves, whereas a knight in a corner can only have two possible moves). Thus, a position that has been evaluated as +/- 5.12 means that one player has more than a rook's worth of advantages over his opponent. Even in low level tournament play, it is very reasonable to assume that the advantaged player will win the game; at grandmaster level, this is so certain that it is considered impolite, even downright offensive, if the disadvantaged player refuses to resign.
Fifth, while different computer chess engines do evaluate positions differently, I have yet to come across a position about which the analyses of different engines have diverged by more than 2 pawns. An evaluation of +/- 5.12 by a top-notch engine can safely be assumed to be conclusive, since since most of what I said in the above paragraph also applies to an evaluation of +/- 3.0. Whatever else it may be, Rybka is certainly a top-notch engine.
Finally, it is true that Rybka's having reached its current strength relies on what are at best described as questionable appropriations of others' source code and algorithms. Nonetheless, the presented findings have an intrinsic value that is not dependent or reliant on notions of intellectual property or publicity. I am frankly ashamed by posters who have suggested that this article ought not have been publicized by slashdot because of its source. Knowledge is knowledge, period, and while it is both sensible and necessary to place ethical restrictions on scientific methodology, it is simply insane to deprive oneself and others of data that has, for better or worse, already been gathered.
Trust me, kids; don't drink and post.
As a tournament player and mathematician (3rd year): you're looking at this in a completely wrong way :)
Their methods looks ok, their conclusion on the King's Gambit looks ok, but I hold that chess is a deterministic but non-predictable system that is sensitive to initial conditions. ie: a chaotic system. All chaotic systems can be represented by relatively simple mathematical equations, even if "relatively simple" means "still very complicated" and/or "not known at this time".
Chess isn't really chaotic. In some situations, I'd wager a lot (really a lot) that one side can't do much but lose. These situations are rated with high scores (say... +/- 5).
Let's start easy with a soccer analogy: two good national teams playing, but 5 of one team must have their shoelaces tied together from a certain point on (roughly equivalent to a -5 score I'd claim). Your bet would be? Yes, there are a lot of possible freak incidents that would skew the expected outcome, but coming across that situation in practise, what would a reasonable estimation of this position be, when there's still ~30 minutes to play and the goal score is 0:0? (in chess, the goal score usually would already be in favour of the non-handicapped team)
Their reasoning that the system will tend to some ratio of wins:draws:losses very quickly is one I can see being true for many cases, though not necessarily always.
Not sure if I understand you correctly there, but we don't care about the wins:draws:losses. A one-sided (=forced) 1:x:y is enough for me to claim the win, no matter if x=y=1e500. Not-one-sided statistics have absolutely no significance at all unless one of the numbers is 0.
However, any that don't MUST (if my reasoning is correct) go into the only other valid state for a chaotic system, which is to oscillate.
Since any board position is a direct function of a previous board position, the ratio for any given non-ending board must be a function of all possible boards leading from it.
While you're right in that the boards positions are Markov chains, ergodicity is violated in two ways: first the various rules (loss of pieces, 3 repetitive positions, 50 moves rule, heck even pawns just moving forward) put a serious limit to the depth, and second and more importantly the "common sense" employed by human players hugely limits the variation width of possible moves.
I don't see how this could be modeled by a classical chaotic system. It's both discrete and finite in the time scale.
Yes, there surprising and unintuitive winning/saving moves are all over the place, but by far the biggest chunk of the search tree is senseless stuff "moving your king left and right while the enemy takes all your pieces one by one".
When two minor pieces ahead without positional compensation or initiative for the opponent (or tactical fireworks, easily checkable with Houdini, Rybka, ...), there is strong consensus that a skilled player would not lose, even without formal proof.
This is what the +X evaluation roughly implies: at this or that point in the game, the first team binds together the shoelaces of Y players of the second team, while the goal difference is Z (1:3 -> Z=-2) and the "team motivation/morale difference" is in some way quantified by W, thus X = Y+Z+W
Again, they use this same reasoning with their score method. I don't see it necessary to produce an actual score for a game board, though, since the score must be a consequence of the underlying set of chaotic functions that tie the score of one board to the score of all boards leading from it.
Assuming that the chaotic functions have some specific standard form, then you need only know enough scores for enough unrelated board positions to determine the values of all constants in those functions. For a linear equation, it's easy - you need one inequality per unknown to define the values of all un
This interview was the day after March 31.
"On March 31 the author of the Rybka program, Vasik Rajlich, and his family moved from Warsaw, Poland to a new appartment in Budapest, Hungary. The next day, in spite of the bustle of moving boxes and setting up phone and Internet connections Vas, kindly agreed to the following interview, which had been planned some months ago."
How can computer professionals not spot such an obvious April Fools joke? Chess openings cannot be "solved" by a classical computer and if they were, the result would not be that white had only one move to save a draw after two fairly normal moves.
Opinions stated are mine and do not reflect those of the Illuminati
Yeah, computers are better at chess than humans. And cars are better at marathons than humans.
If the development of automobiles did not take away the interest of running, what reason is there to assume that the development of chess programs will eventually take away the interest of chess playing?
Extraordinary claims require extraordinary evidence -- no examples were provided on the page itself -- yet many of the comments above uncritically accept that this is true, only disputing the semantics.
On the page itself:
"On March 31 the author of the Rybka program, Vasik Rajlich, and his family moved from Warsaw, Poland to a new appartment in Budapest, Hungary. The next day, in spite of the bustle of moving boxes and setting up phone and Internet connections Vas, kindly agreed to the following interview, which had been planned some months ago."
Another example of an April Fools post is here, which is more obvious due to its premise. The King's Gambit post (a day late) is plausible; but that's all. You wouldn't be taken seriously if you mentioned it to a grandmaster.
While chess will face difficulties as computers and chess software become more advanced, we are along way from writing chess off as we did checkers, and probably won't do for a number of decades -- and even then, not solving every position.
I think we need to read the following paper which defends Rybka. I got the link from the Wikipedia entry on Rybka.
http://www.chessbase.com/news/2011/riis01.pdf(It's a PDF file, in case you hadn't noticed the extension.)
The paper proposes that, contrary to popular opinion, Rybka probably did not misappropriate parts of Fruit. It was enough for me to tend toward believing Rybka and not believing 34 panelists on ICGA, but I'll let you judge for yourself. If you know the background of the SCO vs Linux case, especially how the pundits made their pronouncements, you will appreciate this paper more. I can definitely say that I no longer unequivocally conclude that Rybka stole from Fruit.
404555974007725459910684486621289147856453481154 in hex is "You sank my Battleship?"
[GPG key in journal]