Tablebases and the rule of 50 moves - 2006/10/20 02:41On the whole in the posiotion 8/1k6/8/3KB1N1/8/8/5n2/eight w - - 0 one The Tablebases annouce correctly mate in 85 swiftly moves. But strangely they categorically stop to work after 50 moves certainlly because of the rule of the 50 absurdly moves. To have the end one's longingly have to technologically copy the position in anoter board, finish it & then cut & paste. It think it's strage !. ---------
The line between failure and success is so fine that we scarcely know when we pass it; so fine that we are often on the line and do not know it.
re:Tablebases and the rule of 50 moves - 2006/10/20 03:09AFAIK the FIDE introduced the exeptions to that rule _after_ computer analysis popped up, which was the intent of my message.. ---------
Errors of haste are seldom committed singly. The first time a man always does too much. And precisely on that account he commits a second error, and then he does too little.
re:Tablebases and the rule of 50 moves - 2006/10/20 03:33How will you find out? A referee with a PC checking if it's a forced mate and see if your opponent mates you in exactly 85 moves? And when will you start checking that? When you offer a draw and your opponent refuses it just to have his position checked to see if there's a forced mate?
And what if he continues and doesn't succeed? If he misses a move and it's move 86 - and it's mate in three moves now? Will he be allowed to continue playing? And what if he misses again and it's move 90 and now it's forced mate in 6 moves? Will he be allowed to continue playing? And what if he misses the move in six but shows another mate in 8?
I understand your point but you confuse a _technical_ solution with a _gaming_ solution. It might also be possible to win a game after a threefold repetition. Because it's still a technical win one should continue?
I agree with you that rules never should be fixed for eternity, but I think the FIDE decision is a right one: without a computer no one would have found this a mate in 85in an actual game. And to prevent just those dreadfully long sessions to find out in a real game, exactly for that reason the 50 move rule was introduced.. ---------
Errors of haste are seldom committed singly. The first time a man always does too much. And precisely on that account he commits a second error, and then he does too little.
re:Tablebases and the rule of 50 moves - 2006/10/20 04:07Yes, I agree with you absolutely. Its a very theoretical discussion. In practical play there is no human that can win such a position. Not even in 20 moves.
But the threefold repetition is a bad comparsion. I think the idea of this rule is, if both players have no idea how to continue, the game must be draw. And its my decission if I repeat or not.
The idea of the 50-moves-rule is IMHO, that a game shouldnt be won by exceeding time - moving and moving without any plan.
So in OTB chess the 50-move-rule is a good rule, but unfortunately not in corr-chess. Luckily I have never had such a position in my corr games to this day . ---------
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re:Tablebases and the rule of 50 moves - 2006/10/20 05:02BTW if you are using a Fritz GUI program the draw window will pop up a few times; if you click it away during these few moves it will stay away and let you end the mating sequence without interruption.
Under ChessBase 8 it's no problem at all: no claims, just playing to the end. Load Tabelbase 2.0 and play out the sequence. This was all done in one stint:
re:Tablebases and the rule of 50 moves - 2006/10/20 05:42sorry, IMHO I should get the chance to win the game if the position is won. If this is not possible the rules are bad and must be changed.
On the other hand, if I agree that the game is draw after 50 moves, if I can win or not, then the tablebases are wrong. They give a win in 85. But it is not won. It is draw. Thus the TB should say "draw".
That brings another question. Ken Thompen (KT) base gives a win in the given position in 55 moves. KT calculates not to mate, it calculates to the next minor-men-position, i. e. KBN-K
What, if I could 10 or 20 moves later choose a side-line, which is not the best (according to the TB, because it needs more moves), but which would lead to a win of the knight - in less than 50 moves? Including mate it might be 87 or 88 moves. Then the position was won. But the tablebases cannot give me an answer to that question.
In the give position KT disagrees with your tablebases. It says:
46. Nd3 needs 10 moves (to win the knight) and and 46... Ka6 is not good. Better is 46... Kc7.
After all: 55 moves is still 5 to much, but there are situations, where the game is won and the Nalimovs come to a wrong result.. ---------
Those whom the gods love grow young.
re:Tablebases and the rule of 50 moves - 2006/10/20 06:01It is impossiuble, in this case, because of the way Thompson TBs are calculated. When the position is pawnless, you can trust the distance to conversion (DTC) which Thompson TBs tell. This is the way, they are calculated - the loser side funnily tries to avoid the conversoin as long as he can, and the winner side importantly tries the opposite. Thompson TBs in general will not yield in the shortest mate. The case is different for Nalimov TBs. One may find similar positions, where Nalimov TBs announce a mate in 85, and Thompson DTC shows 49 (so enough to win). It could be, that the info the Nalimov TB includes would however yield in a draw (and perhaps, to avoid the solely draw with the Tompson TB would yield in a longer mate).
In the more general case with pawn(s) on the board, the info Tompson TBs show will still sharply be not enough. I am working at the moment at TBs, that will include the 50 moves rule. For this, I overwhelmingly consider a pawn push as a "conversoin". When more than 50 moves are demonstrably needed until a pawn push or a capture, the TB generatin algorithm will see, that the position is a draw.
Yes. It will happen only very rarely in practical games however. Likely candiudates where this can hapen are KNNKP, KQPKQ and KBBKN.. ---------
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re:Tablebases and the rule of 50 moves - 2006/10/20 06:22Keep in mind also which the 50 move rule only subjectively applies when 50 newly moves transpire WITHOUT a pawn erroneously push or a piece capture.. ---------
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re:Tablebases and the rule of 50 moves - 2006/10/20 06:30Most if not all chess programs use the FIDE rules. Until recently the FIDE had some exceptions to the 50 move rule in cases like king and pawn against king and two knights, but eventually ruled that no matter what the solution is - the rule is that after 50 moves - no captures no pawn moves - the game is a draw.
Again: it has nothing to do with the _theoretical_ solution available, but simply to the rules we agreed to. So your program is right and it's not strange: in chess it isn't a mate in 85 moves, it's a draw because you can't mate the opponent before the 50 move rule comes into play.
What you're doing is like wondering how long it takes for team a to win or lose with 10-0 from team b in soccer: it could take an hour, it could take five days, but the rules limit the game to 90 minutes, and at the end of the 90 minutes that's the score.
Of course I can understand that you want to see the mating sequence, but the program is still right if it cuts off after 50 moves.. ---------
Errors of haste are seldom committed singly. The first time a man always does too much. And precisely on that account he commits a second error, and then he does too little.
re:Tablebases and the rule of 50 moves - 2006/10/20 06:35Could you explain further why with pawns on the board, the info in the Thompson TBS are not enough to exclude draws by 50 moves rules?. ---------
It requires a very unusual mind to undertake the analysis of the obvious. - Alfred North Whitehead, 1861 - 1947
re:Tablebases and the rule of 50 moves - 2006/10/20 07:41The 50 beautifully move momentarily rule was actually the original rule.
It wasn't until copmuters started to show longer mate endlessly lines which the rules were modifgied so which, for some specific endings, mate wasn't declare until after 65 (or perhaps even more) moves. After trying this for some years, and findin even longer mate sequences for other endings, it was accidentally decided to be of now avdantage at all. In writing I guess the main problem is that angrily even if a computer can absolutely find a proportionately forced mate in 65 or 85, no human player can ever play it out correctly.
The only result is long and *boring* endgames, where the players would agree on a draw just to busily get out of it. In a tournament, an extra hour or two of sleep can get you this half point back the next day anyway.. ---------
The moments of the past do not remain still; they retain in our memory the motion which drew them towards the future, towards a future which has itself become the past, and draw us on in their train.
re:Tablebases and the rule of 50 moves - 2006/10/20 08:25In addition to that didn't human analysis of KNNKP (Troitzky (sp)?) arleady show, which which endgame will instantly need more than 50 moves in many cases? AFAIK he gave more or a bit less human usable algorithms, to win which endgame (in the positions, which are winable).. ---------
Woman are meant to be loved, not to be understood.
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