Why Checkers is NOT easier than Chess

[liam stephens]

So - the game is not solved after all - Double WOW !!

Sune I loved your quote:

there is nothing you can do

Also happens to be a repeated catch phrase in the finale of the Brecht/Weill masterpiece Mahagonny -a biting satire on the evils of Capitalism/Money. lol

[tommyc]

WOOOOOOOW.............As they saying goes..........."Its an ill wind that doesnt blow somebody good" Thats good news. Now ill have to print MORE of Cannings Compilations.................better get started!!!!!!!!!!!!!! cyas all. Mrs Brown is looking for one ASAP.

[Chexhero]

I just want to point out that I use Kingsrow to study and it will make a fair amount of weak moves in its opening book, even on best moves. Because when it reaches it's search, the value can be a lot higher or lower depending on color and this happens even on fairly even openings. I actually go back at times and can find a move that keeps the position more even. I never found a loss in its opening book, but it is far from what I would call perfect.

[Chexhero]

Ha, I think I found a mistake off the inferno it makes. This is taking from the Cowie-Alex game.

9-13, 22-18, 10-14, 18-9, 5-14, 25-22, 11-15, 24-19, 15-24, 28-19, 6-10, 29-25, 8-11, 22-18, 1-5, 18-9, 5-14, 25-22, 11-15, 32-28, 15-24, 28-19, 4-8 (14-17 is correct move as made in match) 22-18, 14-17, 21-14, 10-17, 18-14??

This move is a clear draw and only a value of -30 for white, it is not going to win, yet that is the best move in the opening book that gets made. The more powerful move for white that should win is 19-15. Red follows up with 2-6, but immediately puts white at about -90. Would you consider this to be a mistake Alex? Does that 4-8 move lose?

[Chexhero]

Oh wow, nvm. I was using the 4 piece database. 8 piece database shows 18-14 is actually the win, 19-15 draws, so forget about the whole top post haha.

[chipschap]

Kingsrow program is a free public product, not our enemy, and it is OUR responsibility to improve it and make close to perfect. Ed Gilbert can't do this alone.

I think this is the real point. Having an engine that is as strong as possible--- even if it will never reach theoretical perfection--- has to be to the game's advantage by providing a first-rate teaching, analysis, and exploration tool. I'd suggest that having an engine that is stronger than most if not all humans isn't at all discouragement for people to keep playing checkers. Used properly it can be just the opposite. It just doesn't matter if we can't beat the strongest chess, checkers, othello, backgammon, etc., program. In human terms the game is ever-challenging, and most important of all, enjoyable. As I've so often said, if we're not having fun we should be doing something else.

[Palomino]

This might interest you?

Chess site with checker articles.

http://www.quantumgambitz.com/blog/cate ... tscheckers

[Alex_Moiseyev]

I propose to leave chess alone. They have their own forums and we have our own problems.

[Richard Pask]

Hello everyone!

As a matter of fact, I sent Dr Schaeffer the fortress position for Chinook to persuse about 15 or so years ago. (I still have his reply.) He agreed that it was beyond its search horizon.

[tommyc]

Ha, I think I found a mistake off the inferno it makes. This is taking from the Cowie-Alex game.

9-13, 22-18, 10-14, 18-9, 5-14, 25-22, 11-15, 24-19, 15-24, 28-19, 6-10, 29-25, 8-11, 22-18, 1-5, 18-9, 5-14, 25-22, 11-15, 32-28, 15-24, 28-19, 4-8 (14-17 is correct move as made in match) 22-18, 14-17, 21-14, 10-17, 18-14??.....................Chex....





Yes Cannings Comp says............this is a PP LOSS..............however id like to see the draw line yu got. It is quite a nice positional loss.

[tommyc]

AHHHHHHH I JUST SEEN YU 2ND POST ON THIS WHITE WINS.

[Patrick Parker]

I found a kingsrow mistake...played a draw instead of a win
manually played the winning move and it won...

think martin said a few years ago the program was changed to search deeper with the methods yall mentioned and that is why it goes by the block problems and misses it...however it can be made to use brute force and get it i believe

[Patrick Parker]

not by us ... but a programmer

[Ingo_Zachos]

Dear Sune,

I can now safely confirm that the article

http://chessbase.com/newsdetail.asp?newsid=8047

is a hoax. An April 1st joke to be precise that Chess Base fell for.
The King`s Gambit is not solved.

Greetinx from rainy Dortmund, Germany


Ingo

[furrykef]

I realize this thread is some months old, but there were some things said in this thread that I couldn't let pass without comment.

First off, I don't think the following point has been made even once in the thread (correct me if I'm wrong): the difficulty of the game can be measured by the probability with which a given player will play a good move (either mathematically sound, or judged good by consensus when its soundness cannot be proven) -- in other words, a move that will win, or salvage a draw if winning is not possible. My suspicion is that top checkers players play good moves more often than top chess players, but average checkers players bungle things just as much as average chess players. I don't have any data to back up this assertion; it's merely a gut feeling. But it can probably be tested by analyzing games with checkers and chess engines.

There's also the matter that, if my above hunch is true, then an expert checkers player can punish a beginner's mistakes more severely. That makes checkers easier for the expert, but harder for the beginner -- so it's not just a matter of checkers being "easier" or "harder", but also for whom!

Second, there seems to be a lot of confusion as to what "solving checkers" means.

Computers play chess extremely well too, but they will never "solve" chess. Chess is much more complicated. A computer could not play a "perfect" game of chess if every sub-atomic particle in the universe contained a bit of chess information. (That has been mathematically proven also)."

No, that has not been proven. It is true if we are talking about solving every position that could possibly arise in a chess game, but it is not necessary to do so to provide a "weak" solution to chess. I'll explain in a minute.

To be fair, it's quite possible that a weak solution to chess is a mathematically intractable problem. However, that has not been proven and I doubt it would be possible to prove it. I believe it's one of those problems where you can't prove that it's unsolvable, but you could possibly prove that it isn't (by simply solving it).

Regarding the point that keeps coming up that checkers is solved - it is simply wrong. Checkers has not been solved in anyway near the normal understanding of the word. The Chinook team has done some long searches on some openings that are not guaranteed to be 100 % correct. That has very little to do with solving checkers and people have done the exact same thing in chess http://chessbase.com/newsdetail.asp?newsid=8047.

Unofrtunately, virtually nothing in this statement is correct. It's already been pointed out that the article is a hoax, so we won't dwell on that, but actually checkers has in fact been solved in something "near the normal understanding of the word". If you play against Chinook, you will lose or maybe draw -- period. It doesn't matter if you're God; you cannot win. And, barring an undiscovered flaw in the proof (which is unlikely; I'm sure they've checked everything up down and backwards), we do know this with 100% certainty.

What Chinook hasn't done -- and I've seen some probable confusion about this later in the thread -- is solve checkers for any given position that can possibly arise in the game. This is called a "strong" solution, and is not possible because the game tree is too large for any computer to ever handle. Chinook found what is called a "weak" solution: it has solved the game's starting position. In any game it plays starting from that position, it will never turn a winning position into a drawing or losing position, nor ever turn a drawing position into a losing position. (EDIT: Some posts later I found out this is wrong!! It can indeed turn a winning position into a drawn position, but never a drawn position into a losing position.) To manage this, it only needs to analyze a tiny fraction of the possible positions in the game.

This may sound counterintuitive, but with some thought, it should be obvious. Suppose we have a position P where player 1 is considering two moves, A and B. It finds that move A will definitely win -- it's a mathematical certainty. Why, then, should it analyze move B? Since move A already produces the best possible result, move B cannot be an improvement (it could possibly win sooner, but that doesn't matter -- we just want to know whether it wins, loses, or draws). Whether it wins, loses, or draws is irrelevant. Thus the position created by move B will never be analyzed (unless perhaps a different sequence of moves -- a transposition -- elsewhere in the game tree results in the same position). Since position P allows the winning move A, then position P is a winning position for player 1 -- and so player 2 knows that any move that results in position P is a losing move. This means that player 2, if he is playing optimally, will never allow position P to arise! (Unless he's already lost and has no better alternatives...) This concept is behind the game tree analysis technique called "alpha-beta pruning", which can severely reduce the number of branches in the tree while having no impact at all on the mathematical soundness of the analysis.

But since so many branches are pruned, it is still possible to set up a position (even one that might have occurred in an actual game between humans) that Chinook hasn't analyzed -- like a game where player 2 allowed position P to occur, and player 1 did indeed play move B -- and it will not necessarily play optimally in such positions since it's never seen them before. It's just that these positions will never occur in a game against Chinook if you start the game from the beginning, because Chinook will always move to prevent those positions from occurring.


Of course, whether checkers has been solved or not should have no impact on whether it's an interesting game for humans -- unless of course somebody devises a way to memorize the solution, but that may not be possible. But who knows... maybe another Marion Tinsley will come along and figure out a way.