25 votes
Accepted

Will quantum computers solve chess?

I'm not an expert on quantum computation but my understanding is that quantum computers are not expected to be useful for chess. Quantum algorithms are very good at finding needles in haystacks: the ...
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17 votes
Accepted

Do Stockfish and the tablebase work together or independently?

play the game until six pieces Stockfish doesn't do that, that's not what tablebase is for. Briefly, tablebase boosts engine search well before six-men position reached on the board. Let's do an ...
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  • 21.4k
17 votes
Accepted

Are there attempts at creating practical endgame tablebases?

There is a contradiction in terms in "only" generating practical endgame tablebases. We have to understand how tablebases are generated to see why. Tablebases are generated by working backwards from ...
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  • 4,830
16 votes
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Is there a freely available online 7 piece Endgame tablebase?

Original Answer: 7-men Lomonosov is free as an Android application. Update - September 2018: 7-men Syzygy is available for free. Also available from Lichess.
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  • 4,322
16 votes
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How does Syzygy store its information?

Since there is no single comprehensive publication this is based on the probing code, the generator and various explanations from Ronald de Man (the author of the generator). When probing pretty much ...
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  • 427
14 votes
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What is Syzygy tablebases?

Tablebases are databases of endgame positions, with few pieces left on the board (say a 5-man tablebase, which consists of all legal positions with 5 pieces on the board in total, including kings, say ...
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  • 1,303
14 votes

What do DTM, DTZ, DTC, DTR, DTZ50, and DTZR mean?

In various endgame tablebases, the terms mean as follows: Depth to Mate. For each position that is represented, 'DTM' indicates the theoretical value, and the number of winner's moves to 'Mate' if ...
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12 votes
Accepted

What percentage of the time does White win in the Lomonosov tablebase?

As I do not have access to the full Lomosonov tablebases, here is an answer based on the Syzygy tablebases, which are available online in machine-readable format. I interpret your question as "...
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  • 849
11 votes

Does the Lomonosov Tablebase (and others) include extra material positions such as KQQvKQQQ?

The Lomonossov tablebases include all 7-man positions with the exception of 6 pieces vs lone king. Most material distributions you consider "ridiculous" are in fact required to evaluate "interesting" ...
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  • 664
10 votes
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Endgame Tablebases-What are they?

Endgame tablebases are essentially databases containing known endgame positions that have been “solved”, so to speak. That is, every position in an endgame tablebase will have a corresponding result ...
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  • 336
10 votes
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How far from solving chess are we?

Currently most of the 7-piece Lomonosov tablebases have been created. the only ones that weren't, were the K vs. K + 5 pieces. Those took about 6 months using the Lomonosov supercomputer. Based on ...
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  • 3,924
10 votes
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Tablebases say this position is drawn, but Stockfish disagrees-What does that mean?

If the tablebase says that it's a draw with optimal play from both sides, then you can always ignore whatever Stockfish or any other engine says. The tablebase knows the objective evaluation for any ...
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8 votes
Accepted

How is it possible that the Lomonosov-endgame-tablebase from 2012 still is the most powerful tablebase?

I am a developer currently working on software to compute endgame tablebases. The real bottleneck with calculating positions is not memory per se but the working memory and computing cycles needed to ...
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  • 196
7 votes

Is there a freely available online 7 piece Endgame tablebase?

http://chessok.com/?page_id=27966 History Note The first ending tablebases - for all 4-piece endgames - were built by the end of the 80-s. In the beginning of the 90-s, the same task was done for 5-...
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7 votes

Longest way to mate with 1 queen against 4 queens

This max-DTZ position is mate in 8, but probably also a dead-end because it seems hard to improve starting here. [FEN "7q/4q1q1/8/8/3q2Q1/1K6/8/1k6 w - - 0 1"] 1. Qf5+ Qde4 2. Qf1+ Qe1 3. Qd3+ Ka1 4....
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  • 427
7 votes

Why are tablebase files so large?

For a simple numerical example, take the endgame of King + Rook + Pawn vs. King + Rook. The number of possible positions is 64 x 63 x 62 x 61 x 60. Of those, 25% is not valid because the pawn is at ...
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  • 23.8k
7 votes

How far from solving chess are we?

Not only are we far from solving chess, in all likelihood chess will never be solved. There are more possible positions in chess than atoms in the known universe, so not only would in take forever (...
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6 votes

Is there an online database for the endgame KRPPKRP?

All of the Syzygy tablebases are available here: https://syzygy-tables.info/ These cover all endgames up to 7-man, and provide WDL (win-draw-loss) and DTZ (distance to zeroing move) data. Syzygy ...
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  • 1,659
6 votes

Longest way to mate with 1 queen against 4 queens

The best I could come up with is 7 moves, I don't believe it could take much longer, because with 4 queens there's not as much freedom as with 2, I cannot put black king in the middle of the board ...
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  • 1,696
6 votes
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Does the Lomonosov Tablebase (and others) include extra material positions such as KQQvKQQQ?

The Lomonosov Endgame Tablebase supports 7 pieces. That means it has all the positions you describe in your question. Otherwise, it's not a tablebase by definition. The "ridiculous" positions you ...
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  • 21.4k
5 votes

Is there an online database for the endgame KRPPKRP?

There exists a 7-men-endgames tablebase available online, the "Lomonosov endgame tablebase". see : http://chessok.com/?page_id=27966 Unfortunately, it is not free yet.
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  • 905
5 votes

Is there a freely available online 7 piece Endgame tablebase?

The 7 piece EGTB is not yet freely available online, as far as I know. Building the tablebase is costly in time and resources and the storage space is not cost-free either. Concerning http://tb7....
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  • 171
5 votes

How many positions are there in n-pieces endgame tablebases for different values of n?

This depends a great deal on how (and what) you count. In a discussion at the CCRL board, Kirill Kryukov offers the following counts on the number of unique legal positions (NULP) for some small ...
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  • 23k
5 votes

What is the maximum DTM with K+J vs K?

I don't know the exact answer for the 10x8 board (used e.g. in Capablanca Chess, where your Janus is called the Archbishop), but I have something that could get you well along toward an exact answer, ...
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  • 23k
5 votes

What is the maximum DTM with K+J vs K?

I make it 21 moves, but it's quite likely that my home-made Python code (too long and messy to post here!) has mistakes, so please take this with a grain of salt. I get 112 positions which require 21 ...
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5 votes

Chess endgame database+50-move rule=potential error?

You are right that tablebases do not automatically contain information pertaining the fifty move rule. To use tablebases accurately currently engines use the DTZ50 metric (distance to zeroing with ...
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5 votes

How far from solving chess are we?

We are very very far from solving chess. We would need a 32 man tablebase for that. Currently, we have a 7 man tablebase. Each increase of 1 step, requires exponentially more computing power and ...
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  • 207
5 votes

Has Explainable AI been applied to the endgame tablebases?

In short: yes. Although I don't have an overlook on current research. But already with the endgame KR/K, which is as much the drosophila of tablebases as chess is for KI, was handled this way, and for ...
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4 votes

Is there a freely available online 7 piece Endgame tablebase?

https://syzygy-tables.info/ allows to look up 7-men endgame positions. It does not give DTM information for 6- and 7-men endgames, only DTZ50+. On one hand, it is compliant with 50-move rule, OTOH, ...
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  • 121
4 votes

How long would it take China's Tianhe-2 Supercomputer to produce an 8-man tablebase?

From the bottom of this page: Unfortunately the size of 7-man tablebases (sic. - the author means 8-man here) will be 100 times larger than size of 7-man tablebases. To fully compute them, one will ...
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  • 3,178

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