8848.5 moves long. But 5800 or 8848.5 moves long makes no practical difference. Either is impossibly long with current technology and ideas if the starting position is a draw. If it's a mate in 16 that's different.
(That's competition rules post 2017 of course. Under FIDE post 2017 basic rules or pre 2017 rules the longest game is infinite.)
Here is a video showing the longest game possible in chess. And the exact number of moves is 5898 moves. And the video also shows how this number was calculated. Pretty cool!
That's the trouble with videos. It's not. It's 8848.5.
Read the link.
(They probably meant 5899 anyway, or 5898.5 at any rate, depending on how you look at it.)
Imagine a chess position of X paradigms.
Now, a chess computer rated 3000 solves that position. All well and good.
Could another computer rated a zillion solve that position better than Rybka?
No, because not even chess computer zillion could solve the Ruy Lopez better than a sad FIDE master could.
the point is, there's chess positions with exact solutions. Either e4, or d4, or c4, etc.
nothing in the world can change that.
So if you are talking about chess as a competitive sport, then chess has already been solved by kasparov, heck, by capablanca.
If you are talking chess as a meaningless sequence of algorithms, where solving chess equates not to logical solutions of positional and tactical prowess, but as 'how many chess positions could ensure from this one?'' type of solutions, then, the solutions are infinite.
So can chess be solved? If it is as a competitive sport where one side must, win, then it has already been solved. Every possible BEST move in chess has been deduced long ago.
If chess is a meaningless set of moves, with no goal in sight, then sure, chess will never be solved.
absolute nonsense. chess is an abstract game and it is not infinite, really huge, but not infinite, it's possible that in the future chess will be solved by a computer using a smart algorithm. I think maybe one day computers prove that chess is a mate in 200 from the starting position. and the only very best move is e4 and not d4 or vice versa. but even after that day chess will stay a competitive sport and people start the game with different openings.
absolute nonsense. chess is an abstract game and it is not infinite, ...
Depends on which rules you pick. Only finite under FIDE competition rules since 2017. Still infinite under FIDE basic rules and infinite under basic or competition rules prior to 2017.
Doesn't stop there being a solution.
e4 e5 for black is unbreakable. Chess will unlikely be solved in our lifetime
@7093
"Final position has 10 men. In which 7 man tablebase did they look up the draw?"
++ Recapture Kxf2 is forced, then Rf6+ and Rxf7
++ If you start analysing chess then you hit a 7-men endgame table base draw after 33 moves i.e. 66 ply in some branches of optimal play by both sides; after 44 moves i.e. 88 ply in half of the branches; after 60 moves i.e. 120 ply most of the branches and after 120 moves i.e. 240 ply all branches.
Chess never reaches the 5898.5 move maximum: that is by 49 useless moves hopping around, then a 1 step pawn move, then 49 useless moves hopping round etc.
After 120 moves of perfect play the game ends in a draw in all branches.
"Mine was faster anyway." ++ But yours was no optimal play from both sides.
@7094
"So how can a group of GMs (smokers or not) be expected to recognize perfect play?"
++ They do not, and they do not need to: it is the 7-men endgame table base that pronounces the verdict. If whatever you try for white leads to a 7-men endgame table base draw or a prior 3-fold repetition, then Chess is weakly solved.
"How can we rely on their decisions as to which lines to ignore?" ++ That is why they need to be (elder) (ICCF) (grand)masters. They only ignore lines they are sure of like 1 e4 e5 2 Ba6?
"By the time this five-year "solution" process is complete it will be out of date."
++ No. Without any human intervention and only limiting underpromotions to pieces previously captured it would require Sqrt(10^38) = 10^19 positions i.e. 500 years to weakly solve Chess.
The game knowledge of the good assistants cuts it down to 10^17 positions and 5 years.
"no way Sveshnikov's plan will produce a definitive solution" ++ The only problem is funding.
"a brute force calculation of all possible lines, from the opening position to a hopeless draw"
++ It can be accomplished with 3 cloud engines and 3 (elder) (ICCF) (grand)masters.
"as has been repeatedly demonstrated here" ++ I have repeatedly demonstrated it can be done.
"I hardly expect to live to witness such an outcome."
++ It depends on funding. Maybe you will live when humans walk on Mars, maybe not.
@7093
"Final position has 10 men. In which 7 man tablebase did they look up the draw?"
++ Recapture Kxf2 is forced, then Rf6+ and Rxf7
None of which is forced. Admit it you just couldn't count up to 7 - still can't coz that's 8. (And I'm sure ICCF rules say you've got to reach the 7 man tablebase before you can claim.)
++ If you start analysing chess then you hit a 7-men endgame table base draw after 33 moves i.e. 66 ply in some branches of optimal play by both sides; after 44 moves i.e. 88 ply in half of the branches; after 60 moves i.e. 120 ply most of the branches and after 120 moves i.e. 240 ply all branches.
What on Earth are you talking about?
Chess never reaches the 5898.5 move maximum: that is by 49 useless moves hopping around, then a 1 step pawn move, then 49 useless moves hopping round etc.
After 120 moves of perfect play the game ends in a draw in all branches.
You could be right. But how does that relate to your proposed method of solution? Stockfish doesn't do perfect play.
But Syzygy does.
"Mine was faster anyway." ++ But yours was no optimal play from both sides.
99.9 % of my games are perfect. Got that off the big red telephone to the Gent upstairs, same way you got your ICCF stats.
Here is a video showing the longest game possible in chess. And the exact number of moves is 5898 moves. And the video also shows how this number was calculated. Pretty cool!
That's the trouble with videos. It's not. It's 8848.5.
Read the link.
(They probably meant 5899 anyway, or 5898.5 at any rate, depending on how you look at it.)
I would buy that. When the number around 5800 as an upper estimate was mentioned a few days ago, I thought it was going to be too low. Then I thought that I'll work it out myself from first principles, to check. Then I thought that I've a lot more urgent things to do with my time, such as sitting in a blank state of mind waiting to get older.
Well really, not at all. Much too busy with other stuff.
@7107
"What on Earth are you talking about?" ++ This is the longest perfect game with optimal play from both sides to reach the 7-men endgame table base draw.
https://www.iccf.com/game?id=1164280
It took 119 moves to the 7-men endgame table base draw i.e. 238 ply. All the other perfect games reach the 7-men endgame table base draw or a prior 3-fold repetition sooner.
"But how does that relate to your proposed method of solution?"
++ If you calculate all reasonable white moves, then 1 tentative black response, then all reasonable white moves, then 1 tentative black response and so on then the 7-men endgame table base draw or a prior 3-fold repetition is reached in at most 119 moves, i.e. 238 ply.
Another explanation: chess has 10^44 legal positions. 10^44 = 2^146.
So after 146 digital decisions you get the whole of Chess.
Checkmates that exceed 146 moves exist, but they must contain a string of forced moves.
"Stockfish doesn't do perfect play."
++ Agreed, but that does not matter. Stockfish only needs to generate the reasonable white moves. Stockfish then selects the 1 black response without worry if perfect or not.
If a 7-men endgame table base draw or a prior 3-fold repetition is reached, then that validates all black responses as fit to draw.
"99.9 % of my games are perfect" ++ No, they are not.
"same way you got your ICCF stats." ++ No.
@7107
"What on Earth are you talking about?" ++ This is the longest perfect game with optimal play from both sides to reach the 7-men endgame table base draw.
https://www.iccf.com/game?id=1164280
It took 119 moves to the 7-men endgame table base draw i.e. 238 ply. All the other perfect games reach the 7-men endgame table base draw or a prior 3-fold repetition sooner.
"But how does that relate to your proposed method of solution?"
++ If you calculate all reasonable white moves, then 1 tentative black response, then all reasonable white moves, then 1 tentative black response and so on then the 7-men endgame table base draw or a prior 3-fold repetition is reached in at most 119 moves, i.e. 238 ply.
Another explanation: chess has 10^44 legal positions. 10^44 = 2^146.
So after 146 digital decisions you get the whole of Chess.
Checkmates that exceed 146 moves exist, but they must contain a string of forced moves.
"Stockfish doesn't do perfect play."
++ Agreed, but that does not matter. Stockfish only needs to generate the reasonable white moves. Stockfish then selects the 1 black response without worry if perfect or not.
If a 7-men endgame table base draw or a prior 3-fold repetition is reached, then that validates all black responses as fit to draw.
"99.9 % of my games are perfect" ++ No, they are not.
"same way you got your ICCF stats." ++ No.
y you no accepting friend requests man I like having you on my list I loved how brilliantly you answered the original poster of this forum.
An 8 piece tablebase is a drop in the ocean of chess (a major understatement when you compare the scales).
@7094
"So how can a group of GMs (smokers or not) be expected to recognize perfect play?"
++ They do not, and they do not need to: it is the 7-men endgame table base that pronounces the verdict. If whatever you try for white leads to a 7-men endgame table base draw or a prior 3-fold repetition, then Chess is weakly solved.
"How can we rely on their decisions as to which lines to ignore?" ++ That is why they need to be (elder) (ICCF) (grand)masters. They only ignore lines they are sure of like 1 e4 e5 2 Ba6?
"By the time this five-year "solution" process is complete it will be out of date."
++ No. Without any human intervention and only limiting underpromotions to pieces previously captured it would require Sqrt(10^38) = 10^19 positions i.e. 500 years to weakly solve Chess.
The game knowledge of the good assistants cuts it down to 10^17 positions and 5 years.
"no way Sveshnikov's plan will produce a definitive solution" ++ The only problem is funding.
"a brute force calculation of all possible lines, from the opening position to a hopeless draw"
++ It can be accomplished with 3 cloud engines and 3 (elder) (ICCF) (grand)masters.
"as has been repeatedly demonstrated here" ++ I have repeatedly demonstrated it can be done.
"I hardly expect to live to witness such an outcome."
++ It depends on funding. Maybe you will live when humans walk on Mars, maybe not.
As I understand your explanation/elaboration of Sveshnikov's proposal, analysis will done on only those opening moves the experts consider relevant and will only analyze lines from drawn ICCF grandmaster games that experts believe display "perfect play". This seems to make the entire enterprise reliant on humans and engines that are known to be imperfect. Am I misunderstanding something?
@7112
"analysis will done on only those opening moves the experts consider relevant"
++ Analysis will not be done on moves that are clearly no optimal play e.g. 1 e4 e5 2 Ba6, 1 e4 e5 2 Nf3 Nc6 3 Ng5 etc. It is to not waste engine time on what is already obvious.
"will only analyze lines from drawn ICCF grandmaster games"
++ The drawn ICCF WC Finals games serve as a backbone of already completed analysis as they each already represent 2 years of engine analysis under guidance of an ICCF grandmaster.
It is to speed up the process.
"This seems to make the entire enterprise reliant on humans and engines that are known to be imperfect." ++ The enterprise relies on the 7-men endgame table base known to be perfect.
"Am I misunderstanding something?" ++ Yes
@7112
"analysis will done on only those opening moves the experts consider relevant"
++ Analysis will not be done on moves that are clearly no optimal play e.g. 1 e4 e5 2 Ba6, 1 e4 e5 2 Nf3 Nc6 3 Ng5 etc. It is to not waste engine time on what is already obvious.
"will only analyze lines from drawn ICCF grandmaster games"
++ The drawn ICCF WC Finals games serve as a backbone of already completed analysis as they each already represent 2 years of engine analysis under guidance of an ICCF grandmaster.
It is to speed up the process.
"This seems to make the entire enterprise reliant on humans and engines that are known to be imperfect." ++ The enterprise relies on the 7-men endgame table base known to be perfect.
"Am I misunderstanding something?" ++ Yes
Endless, repetitive, completely unconvincing rubbish and certainly not an explanation of just WHAT you think mpaetz is misunderstanding.
Stockfish - "I am not 100% sure about the move 2. Ba6. Better investigate it a little. Still won't be absolutely sure, but this is essential for practical purposes".
@tygxc - "I can just look at 1. e4 e5 2. Ba6 and know with 1 ply analysis what the result is."
Stockfish - "I guess that's why I'm 1500 Elo points stronger than you".
Stockfish - "I am not 100% sure about the move 2. Ba6. Better investigate it a little. Still won't be absolutely sure, but this is essential for practical purposes".
@tygxc - "I can just look at 1. e4 e5 2. Ba6 and know with 1 ply analysis what the result is."
Stockfish - "I guess that's why I'm 1500 Elo points stronger than you".
I'm not really sure or convinced why you think "Stockfish" isn't "sure" about the result of 2. Ba6, since it's completely clear that Stockfish is programmed not to be sure. I could say the same about IQ points. 
@7107
"What on Earth are you talking about?" ++ This is the longest perfect game with optimal play from both sides to reach the 7-men endgame table base draw.
https://www.iccf.com/game?id=1164280
No it's not.
It's Jon Edwards v Sergey Adolfovich Osipov from the ICCF WC 32, which ended in an agreed draw with 13 men on the board.
This is the same game continued using Arena/Stockfish. It ended with a claim under the 50 move rule on move 236.
It took 119 moves to the 7-men endgame table base draw i.e. 238 ply.
You may as well leave out the endless translations from moves to ply; I think we can all manage it. Especially since you appear to have insurmountable problems counting up to 7.
All the other perfect games reach the 7-men endgame table base draw or a prior 3-fold repetition sooner.
Big red telephone again, right?
"But how does that relate to your proposed method of solution?"
++ If you calculate all reasonable white moves, then 1 tentative black response, then all reasonable white moves, then 1 tentative black response and so on then the 7-men endgame table base draw or a prior 3-fold repetition is reached in at most 119 moves, i.e. 238 ply.
You don't have a reasonable definition of "reasonable".
You claim that all perfect games that are not Jon Edwards v Sergey Adolfovich Osipov from the ICCF WC 32 reach the 7-men endgame table base draw or a prior 3-fold repetition sooner than Jon Edwards v Sergey Adolfovich Osipov from the ICCF WC 32. That's true of perfect games that reach one or other, but only because Jon Edwards v Sergey Adolfovich Osipov from the ICCF WC 32 never reached either.
But perfect games need only perfect moves, they don't have to include moves that tygxc thinks are reasonable. You make no connection between perfect moves and moves that tygxc thinks are reasonable.
Indeed, earlier in the thread you accused the Syzygy tablebase of trolling in this game.
Is it your contention that Syzygy is trolling and all it's moves are reasonable?
Another explanation: chess has 10^44 legal positions. 10^44 = 2^146.
Here you're a victim of your own misinformation.
Tromp's estimate of the number of basic rules positions is 4.82 x 10^44. NOT 10^44.
2^148 < 4.82 x 10^44 <2^149.
So after 146 digital decisions you get the whole of Chess.
By "digital decisions" I assume you mean choices of moves. (Or are you still struggling to count up to 7 on your fingers?)
You make no mention of whether or not the moves are perfect so the continuation of Jon Edwards v Sergey Adolfovich Osipov would be a case in point.
I can't find anywhere in that game the position after 1.e4 e5 2.Ba6. Can you? Wouldn't that be included in Chess?
Neither can I find any of the large number of positions with the same diagram and ply count, say, 13 under the 50 move rule. Would they not also be included in Chess (though of course not in Tromp's number)?
Checkmates that exceed 146 moves exist, but they must contain a string of forced moves.
So far as I can understand your logic (not very far), that seems to rest on on the obviously invalid assumption that the number of basic rules positions associated with the competition rules positions occurring in all continuations is the product of the number of choices of moves in each such competition rules position or something of the sort. Choice of perfect moves maybe?
That would need Tromp's upper bound rather than his estimate for a valid proof (as well as a different argument). Also you would need to say exactly what you mean by "forced" and how many moves constitute a "string". (Do you include strings of one?.)
Here is a provably perfect (just in case it needs to be) checkmate in 148. Can you indicate some strings of forced moves?
Mainly, I can't see your point even if what you say is true. It is to be expected that with most definitions of "forced move" such strings will occur in a long sequence of moves whether as part of a win or draw. Are you trying to make a relevant point or are you just away wi' the fairies?
Edit: sentence reinserted for context ->But how does that relate to your proposed method of solution? "Stockfish doesn't do perfect play."
++ Agreed, but that does not matter. Stockfish only needs to generate the reasonable white moves.
In the vanishingly unlikely event that you ever got a sponsor it might matter to him.
How are you going to make it generate only moves tygxc thinks are reasonable?
Stockfish then selects the 1 black response without worry if perfect or not.
If a 7-men endgame table base draw or a prior 3-fold repetition is reached, then that validates all black responses as fit to draw.
Obviously not.
"99.9 % of my games are perfect" ++ No, they are not.
Are so !
"same way you got your ICCF stats." ++ No.
++Yes. So there !
@7116
"which ended in an agreed draw with 13 men on the board"
++ The transition to a 7-men endgame table base draw is forced.
"This is the same game continued using Arena/Stockfish." ++ Very well, this shows the need for human assistants to cut short such needless calculations and call it a draw.
"All the other perfect games reach the 7-men endgame table base draw or a prior 3-fold repetition sooner. Big red telephone again?"
++ No, statistics. Between 13 and 119 moves, 42 moves average, with standard deviation 16.
"If you calculate all reasonable white moves, then 1 tentative black response, then all reasonable white moves, then 1 tentative black response and so on then the 7-men endgame table base draw or a prior 3-fold repetition is reached in at most 119 moves, i.e. 238 ply.
You don't have a reasonable definition of reasonable".
++ That is just the best first heuristic as used in solving Checkers and Losing Chess.
If the 4 best moves cannot win for white, then the worst moves cannot win either.
"But perfect games need only perfect moves"
++ Statistics applied to the ICCF WC Finals games show they are > 99% sure to be perfect games i.e. they contain optimal moves from both sides.
"Tromp's estimate of the number of basic rules positions is 4.82 x 10^44"
Yes, but the factor 4.82 is irrelevant and should be 1.205 because of up / down symmetry and left / right symmetry after loss of castling rights.
"2^148 < 4.82 x 10^44 <2^149" ++ Yes
"By digital decisions I assume you mean choices of moves"
++ Yes, less than 149 choices between 2 moves, or less than 74 choices between 4 moves.
"You make no mention of whether the moves are perfect or not"
++ That is only legal choice, if they need to be perfect there is even less choice.
"I can't find anywhere in that game the position after 1.e4 e5 2.Ba6. Can you?"
++ It is clear that 2 Ba6? is not optimal play by white.
"Wouldn't that be included in Chess?" ++ Yes, 1 e4 e5 2 Ba6? belongs to the 10^44 legal positions, but not to the 10^17 relevant positions.
"Neither can I find any of the positions with the same diagram and ply count 13 under the 50 move rule" ++ The 50-moves rule plays no role. Games with optimal play from both sides end in draws long before the 50-moves rule would trigger.
"How are you going to make it generate only moves tygxc thinks are reasonable?"
++ Stockfish ranks the legal moves. Then it is the best first heuristic.
If the best white moves cannot win, then the worse white moves cannot win either.
"If a 7-men endgame table base draw or a prior 3-fold repetition is reached,
then that validates all black responses as fit to draw."
++ People here still fail to understand this, though it is simple.
If all reasonable white moves fail to win against a black response, then that black response is optimal. It does not matter how that black response was obtained. It does not matter if other black responses draw as well or not.
If white cannot win against those black responses, then Chess is weakly solved.
If the black responses lead to a table base draw or a prior 3-fold repetition,
then they are optimal in retrospect.
Yes as I remember it's supposed to be 5800 moves. No, all the move permutations are too much to be stored pretty much anywhere. The computational power would be vaster than anything we can imagine at the moment.