24

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 three big quantum algorithms are Shor's factorization algorithm, Grover's database lookup algorithm and the Deutsch–Jozsa algorithm, which essentially ...


21

Seven man end game table bases are already available online: http://chessok.com/?p=28049 By the end of 2013 they should be available off line as well. The size is 140 000 gigabytes so there is an obvious problem with copying them. They did not compute 6 white pieces versus 1 king since they decided it was pointless. Interesting fact- the longest forced ...


15

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 exercise, add the board 5 pieces. Now you have 10 pieces on the board, and it's not something you can find in any tablebase. However, during the engine search ...


15

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 the final mating/drawing positions, "retracting" moves rather than playing them forward. First, every possible final position is exhaustively listed. Then from ...


14

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 any tablebase (aka huge compressed hash map): The position is normalized ... ... mapped to an integer index. The index is looked up in a table that identifies ...


13

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.


13

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 K+Q vs. K+R+B). These databases have the positions 'connected', i.e. they also contain the moves to get from one legal position to another (in particular, ...


11

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 "how often does the side to move win, lose or draw". As the Syzygy tablebases only include positions where White has material advantage, we have to add the ...


10

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 which will either be a win for white, a win for black, or a draw (assuming perfect play). They are used by chess engines because it is much more efficient for ...


9

First, I'm not convinced that engines are necessarily weak without their books. Without an opening book, modern engines might not play the most testing lines, or lines that would get them into a position where they thrive, but any top engine will still crush any human GM without an opening book. As an interesting aside, if you leave your engine on for a ...


9

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" positions because of possible pawn promotions. This works recursively, so if you want to solve e.g. KPPPvKPP, you need (among others) the table KPPQvKPP first. ...


9

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 this answer, creating the 8-piece tablebases could take 100x the time it took to create the 7-piece, give or take an order of magnitude. Extrapolating, that would ...


7

Win against who? I've seen KQ/KR draw between computers before, in 1 or 5 minutes (without egtb). They can drill pretty deep when there aren't many pieces on the board, but if the time control is fast enough, it's not always deep enough. Even GMs draw that one sometimes. Still, I imagine a normal person might make a non-optimal move in such a time control,...


7

The fraction of all six-man positions that are unreachable from the starting position is very, very small. Removing them would have a tiny effect on the size of a six-man database. Here is an example of how rare these positions are. First of all, we can't get into one of these unreachable positions without a bishop and a pawn, so we already have a small ...


7

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-pieces. In 2005, 6-piece endings were solved in Nalimov Tablebases which are now used by many professional chess programs and services. Experts didn’t expect 7-...


7

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 the first or last row, and because of the symmetry around the d/e file, we only need to store the positions where the pawn is on the a, b, c or d file. This ...


7

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 (literally) to traverse the tree, but it would be impossible to store. At current cpu speeds, even with infinite storage, the universe would die of heat death ...


6

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 when capturing black queens while keeping king in check: 3q4/q7/q7/q7/8/8/8/k1K4Q w - - 0 1 And I made it nice as you asked -- the first move it not a capture! =)...


6

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. Qa6+ Qa5 5. Qxa5+ Qa3+ 6. Qxa3+ Kb1 7. Qa2+ Kc1 8. Qc2#


5

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 also distinguishes between a theoretical win or loss that can actually be forced into a draw by the 50-move rule, and one that cannot. Here's an example for ...


5

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 numbers of pieces: Pieces NULP 2 462 3 368,079 4 125,246,598 5 25,912,594,054 6 3,787,154,440,416 ...


5

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.chessok.com/ do not be too disappointed, because they mention this explicitly (at least today, maybe not on April 11th when you tried): "Currently the tablebases ...


5

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, though with some effort on your part (see further below). On the 8x8 board the max DTM is 17 moves (as you may already know). My conjecture is that the 10x8 ...


5

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 fifty move rule) which tells you the number of winning moves until the 50-move count is reset. If this number is too big, the position is evaluated as a draw. ...


4

7-men Syzygy tables are available for download: ftp://ftp.chessdb.cn/pub/syzygy/ Mirrors: http://tablebase.sesse.net/syzygy/ https://tablebase.lichess.ovh/tables/standard/ As of August 2018, only latest development Stockfish (and some of its derivatives) supports them.


4

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, DTZ50-optimal play can be ugly (if it is possible to push a pawn or sacrifice a piece, it will). Also available for download: https://tablebase.lichess.ovh/...


4

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 need about 10 PB (10000 TB) of disk space and 50 TB of RAM. Only top 10 supercomputers can solve 8-man problem in 2014. So don't hold your breath expecting new ...


4

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.


4

This page claims that the longest DTM in this type of endgame is 182 moves. 8/4k3/8/Q7/8/7P/P7/q1K5 w - - 0 1 1. Kc2 Qd4 2. Qe1+ Kf7 3. Qf1+ Kg7 4. Qg2+ Kh8 5. Qa8+ Kh7 6. Qb7+ Kh6 7. Qc6+ Kh5 8. Qe8+ Kg5 9. Qg8+ Kh6 10. Qe6+ Kh7 11. Kb3 Qd3+ 12. Kb4 Qd2+ 13. Kb5 Qd3+ 14. Qc4 Qf5+ 15. Kb6 Qf2+ 16. Kb7 Qf3+ 17. Kc7 Qa3 18. Kb6 Kh8 19. Qd4+ Kh7 20. Qd7+ Kg6 ...


4

I don't know a single source tabulating the winning percentages for all 6-piece endings, but at least some amount of summarizing information can probably be found scattered throughout Nunn's Secrets of ... Endings series of books, which are essentially translations from tablebase to human-usable information. But there is a spreadsheet available from Tamplin'...


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