Questions tagged [tablebases]

Tablebases are databases that contain complete, exhaustively calculated moves and variations for a given collection of chess positions. E.g. the Nalimov tablebases contain full solutions for all endgames involving 6 pieces or less.

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Is there a spreadsheet of all 5 or fewer men endgame tablebase continuations/results? How could one be made?

I am looking for a spreadsheet such as the one here: https://data.world/uci/chess-king-rook-vs-king, except that it covers all 5 or less men endgames. Ideally it would also have PGNs of the ideal ...
2 votes
1 answer
172 views

Finding every longest endgame for each material configuration

I can find statistics on the number of moves until checkmate in the Syzygy endgame table for each material configuration. Let's say I am interested in "KQQvK" endgames. The statistics show ...
4 votes
1 answer
147 views

Finding all critical endgames

A winning position is called critical, if all moves - except one - draw or lose (assuming the opponent plays perfectly). Similarly, a drawn chess position is called critical, if all moves - except one ...
14 votes
1 answer
6k views

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

I need help clarifying the abbreviations and acronyms used in endgame tablebases. Just what do DTM, DTZ, DTC, DTR, DTZ50, DTZR mean?
5 votes
2 answers
2k views

Where can I download gaviota endgame tables?

I am looking for a link to download all 5 pieces gaviota endgame tables (which can give me DTM values). A few links from google search (like this) lead me to the site which does not exist.
0 votes
2 answers
118 views

What is the DTM for White is this 7 piece position?

I know that is winning for White because of the Syzygy tablebases. But Stockfish 14.1 NNUE, without tablebases, returns an evaluation of only +3.23 at depth =72(!). What is White's DTM? [FEN "8/...
5 votes
2 answers
708 views

What is the longest current tablebase mate with a unique optimal line?

Having been inspired by an article on ChessBase.com, what is the longest current tablebase mate with a unique optimal line? By unique, I mean for each of the winning side's plies, there is only one ...
10 votes
3 answers
4k views

Are there attempts at creating practical endgame tablebases?

As I understand it, 8-piece endgame tablebases have been in development for many years. The big issue is the sheer number of positions that are possible. Are there any attempts at making a "practical"...
2 votes
1 answer
96 views

Has Explainable AI been applied to the endgame tablebases?

There's an ongoing trend towards building 'Explainable' AI so that not just the results of a decision process are generated, but also some form of human-readable explanation for it. The Wikipedia ...
2 votes
1 answer
226 views

What is the longest known 7-piece checkmate?

What is the longest known 7-piece checkmate?
4 votes
1 answer
671 views

What is the longest tablebase win that includes draw rules?

It has been asked the longest mate that includes draw rules is, and it is known what the longest tablebase mate is. However, what is the longest tablebase mate, i.e. 7 pieces or less, that accounts ...
1 vote
0 answers
45 views

Long tablebase wins in tournament praxis

I very much assume that KBB/KN endgames already occurred often enough in OTB play, and I also bet the B side always played on for a win (regardless whether this was after the computer proved it was a ...
2 votes
0 answers
47 views

How can I query an endgame tablebase for multiple positions using loops/conditional statements?

In textbooks you find diagrams about key squares and similar concepts. For example, white can promote a pawn if white's king can control three particular squares infront of the pawn. I would like to ...
2 votes
3 answers
271 views

Longest sequence with only moves to draw without a repetition

What is the longest known sequence of moves with upto 6 pieces where each move of both sides is the only move drawing the game (any other move would lose the game) ? There should not occur any ...
4 votes
1 answer
681 views

Mutual Zugzwangs & Longest Checkmates (DTM, DTC and DTZ) in the endgame KRPP vs. KRP

Are there any surveys on mutual zugzwang positions and the longest checkmates (split into categories of DTM, DTC, and DTZ) in the endgame KRPP vs. KRP (King+Rook+2 Pawns vs. King+Rook+Pawn)? In ...
3 votes
1 answer
114 views

Free tablebase generator software?

I'd like to play a bit with fairy tablebases (Vaclav Kotesovec published quite a few) and am far too lazy to program them anew, especially as I wouldn't wonder if there is free code floating around, ...
2 votes
2 answers
162 views

How do endgame tablebases calculate checkmates to do retrograde analysis on?

I understand that once endgame tablebases get checkmates, they do retrograde analysis and are able to calculate forced wins. However, how do they calculate the checkmate in the first place? Do they ...
4 votes
1 answer
284 views

Maximum DTC and maximum DTZ in the endgame KRPKRP

What is the maximum DTC and the maximum DTZ in the endgame KRPKRP (rook+pawn against rook+pawn) ?
4 votes
1 answer
398 views

Obtaining the correct move from syzygy tablebases (Python)

I have created a chess engine in Python and now want to start using the endgame tables in syzygy. I have downloaded all the relevant files and is now ready to start. I have found how to access the ...
13 votes
2 answers
4k views

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

Due to Wikipedia: Endgame tablebase the Lomonosov endgame tablebase is still the biggest tablebase (with a size of 140TB). Now this tablebase was computed in the year 2012 with the Lomonosov 1 (Top500-...
0 votes
3 answers
157 views

On the feasibility of a KBN-K mate within 50 moves using a particular method

Prove that it is possible, from any starting KBN-K position, to accomplish the mate by manoeuvering to arrive at key positions from a well-known method or strategy whilst the losing king actively ...
3 votes
3 answers
989 views

Tablebases say this position is drawn, but Stockfish disagrees-What does that mean?

Today I found myself in the below position as black (me to play). My gut told me it should be a draw, but as my opponent and I are both fairly weak there was a significant chance one of us would ...
0 votes
1 answer
139 views

What is the fifth position in the KN vs. KR endgame with the knight mating?

I can come up with 8 positions where the knight would deliver checkmate to a rook and king. However, on endgame tablebases, there are only 5 positions where a King knight wins against King rook. Why?
4 votes
2 answers
261 views

What are the dates each of the endgame tablebases were completed?

I'm curious to get a rough sense for when chess could be solved if Moore's law, and algorithm improvements continue, and I thought a good way to get a rough idea would be to extrapolate based on when ...
6 votes
4 answers
485 views

Endgame Tablebases-What are they?

I've been reading and enjoying the site immensely. What is the "Endgame Tablebase"? I see it referenced frequently.
4 votes
1 answer
663 views

Generate Simple Mate In 1 From Tablebases (for kids)

I was trying to find a kid's app for chess that has some incredibly simple problems. However, all the apps I found had rather tricky problems. So I thought I would download 3 piece table bases and use ...
1 vote
1 answer
290 views

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

Studies show a slight advantage for White for having the first move. In the tablebase of trillions of 7-piece endgames, with White to move, how many of those endgames end up as wins, how many as ...
3 votes
1 answer
469 views

Longest DTM in the endgame KQPPKQ

What is the longest DTM in the endgame queen and two pawns versus a queen (KQPPKQ? This position is a mate in 167 moves. [FEN "8/k7/6K1/1Q6/8/P6q/7P/8 w - - 0 1"] Are the DTC and/or DTZ ...
2 votes
0 answers
98 views

Stockfish Transposition Table: 16 bit key equals 0 even if the key is found? [closed]

In Stockfish 11, they use the high 16 bits as key inside the cluster: const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster This renders problem when key >> ...
28 votes
4 answers
6k views

What is the status for seven man end game table bases?

There are complete (or nearly complete) six man end game table bases available for download, and even online. What is the status of seven man table bases? Is there still active development in this ...
3 votes
1 answer
279 views

Looking for special chess freeware

I am looking for chess freeware that ideally has the following facilities, and I am wondering what compromises I'll need to accept. I am also requesting the results of your experiences. List Of Needs ...
1 vote
0 answers
95 views

Using Freeware AI and Dynamically Generated Endgame Tablebases [closed]

The purpose of this query is to discuss a topic that I am totally ignorant of, rather than pose one specific question. Although such a query does invite opinions based on intuition, I am also ...
3 votes
1 answer
166 views

ChessBase Nalimov tablebases

I'm using Nalimov tablebases with Fritz14 and it basically works. Just one strange problems occurs: The engine doesn't mate because the final mating move isn't sorted correctly. It look like this: +- ...
3 votes
1 answer
216 views

Is there any method to determine if the weaker side in KQPKQ has a perpetual check?

Is there any possibility to check, without the use of the tablebases, if a position in the endgame queen+pawn vs queen (KQPKQ) allows a perpetual check for the weaker side?
5 votes
2 answers
291 views

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

Are there any examples of positions where usage of the endgame tablebase gives an incorrect evaluation, due to the ignoring of the 50-move rule? At the moment I am not sure if endgame tablebases ...
3 votes
2 answers
603 views

Longest way to mate with 1 queen against 4 queens

What is the longest way to checkmate with 1 queen against 4 queens, with no other pieces on the board? Since there are 13 moves long games with a queen vs two queens, I conjecture this should be ...
30 votes
5 answers
35k views

Can a rook win against a knight in the endgame?

Suppose we have a rook and the opponent has a knight next to his king. Is it possible to win this game theoretically? E.g., in the following position (white to move), is it possible for white to ...
13 votes
3 answers
2k views

Computer endgame strength without tablebases

I have seen that engines aren't particularly strong in the openings without access to a book. How strong are modern engines in the endgame when they are not allowed access to tablebases? E.g., can ...
12 votes
5 answers
1k views

How many legal but unreachable positions exist?

Consider this legal chess position which can never be reached from the normal starting position. [FEN "6kb/6p1/6K1/8/8/8/8/8 w - - 0 1"] The Black bishop is placed on h8, but with the Black ...
6 votes
2 answers
407 views

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

What is the maximum DTM in the endgame king + janus vs king on a 10x8-board ? The janus can move like a bishop or like a knight. Since both sides have two additional pieces, the board has 10 columns ...
12 votes
1 answer
2k views

How does Syzygy store its information?

From reading everything I've found so far, I know that Syzygy uses both win/draw/loss files and distance-to-zero files, but I haven't found any information on the internal file format that these files ...
10 votes
1 answer
3k views

Do Stockfish and the tablebase work together or independently?

I use Arena GUI together with stockfish in engine games. I want to download a 6-piece tablebase but that is just a lot of work (and perhaps unnecessary). If I download the tablebase (syzygy), does ...
2 votes
1 answer
228 views

Looking for a comfortable DTC endgame database

The only online endgame database supporting DTC (Depth To Conversion) that I know of is jaet. Unfortunately for me, the positions can only be entered by FEN. It is not possible to drag pieces, as I ...
6 votes
3 answers
1k views

Syzygy 6 man Tablebase Files Question

Is anyone familiar with the .wdl and .dtz formats for the 6 man tablebase that are available? I already confirmed that both aren't needed, however they both store different information. Goal is to ...
5 votes
3 answers
596 views

Is there an online database for the endgame KRPPKRP?

It was stated at this forum that the 7-men-endgames are still not available online. What about the special endgame KRPPKRP (Rook and 2 pawns against Rook and 1 pawn) ? It would be nice if the ...
4 votes
1 answer
795 views

How to use ending evaluation in UCI interaction with Stockfish

Playing around with the Stockfish 8 UCI from the terminal, I've managed to make it compute moves, and set the position and load Syzygy tables. But how I can know if an endgame, one that corresponds ...
21 votes
3 answers
11k views

Will quantum computers solve chess?

The theory is that there are more that 10^40 positions, and a computer that works with an atomic scale has to be impossibly large(As in galaxy-scale large), and well beyond our current level of ...
4 votes
1 answer
189 views

Tablebases for variant where stalemate is a win?

Since time immemorial, some people have suggested that stalemate be declared a loss for the player who is unable to move. This proposal is sometimes called "abolishing the stalemate rule" although I ...
2 votes
4 answers
400 views

Public higher-order endgame tablebases for *common* positions?

It's easy for me to locate 6-piece tablebases online for free (e.g. lichess), and I know 7-piece tablebases exist (cf. Lomonosov tablebase), but I don't know of any easy way to access them. However, ...
5 votes
3 answers
848 views

What are the winning chances of every pieces? (6men egtb)

Is there a site or document which shows what the winning chances are of every "Specific Pieces vs. Specific Pieces" endgame? e.g. What are the winning chances of Rook & Bishop vs 2 Knights?