Questions tagged [engines]

Questions relating to chess engines: any computer program that is able to play/analyze chess positions.

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10
votes
2answers
856 views

Looking for free versions of older chess engines

In connection with another project, I am looking on the internet for some free versions of older chess engines, such as some of the old Chessmaster engines from the 1990s. I would even take an old ...
2
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2answers
44 views

Python Efficient Board Scoring Function To Use As Placeholder

I'm building a chess engine in Python. I'd like to find a board evaluation function that would be easy to put into my engine as a placeholder while I work on other aspects of the engine first. I would ...
2
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1answer
66 views

Using pgn-extract to output FEN + evaluation

I'm using pgn-extract to convert a PGN database into FEN + evaluations. My goal is something like this: 1. e4 e6 2. d4 b6 3. a3 Bb7 Into this: rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 ...
11
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5answers
2k views

Approximating a rating for too strong engines

Suppose we have an extremely strong engine that happens to win every game it participates in even against the most powerful engines and players. If it continues to win every game, its rating (for ...
1
vote
4answers
124 views

For fixed-depth search, how much is the efficiency different between odd and even moves?

If a chess engine calculates in even depth, in the final position, it has to move again, whereas if it calculates at the odd depth, then the opponent has to move at the end of calculation (ignoring ...
1
vote
1answer
151 views

Average number of moves until checkmate for two players of unequal strenth

Suppose a game is played, until checkmate, between players of unequal strength, say 1800 vs 2800. What would be the average number of moves be for, say, 1000 games? I also ponder 2000 vs 2800 and 2200 ...
9
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5answers
996 views

Evaluation bar cheating - how much does it really give, and how can it be detected?

To start off - due to my anxiety, I do not play any form of chess against other people (except some friends of mine, but that obviously doesn't matter for the context of this post). I recently got ...
1
vote
1answer
154 views

What does "hashfull 1000" mean in Stockfish?

When I use Stockfish, the "hashfull" value climbs up to 1000 and then stays there. I was wondering what this means. The documentation says : * hashfull <x> the hash is x permill full, ...
2
votes
1answer
228 views

What is the best chess engine for 1 CPU?

We have now GPUs, Quad-cores, i7s, i5s, i3s, and so on. However, I am wondering what is the best chess engine for 1 CPU. ChessBase offers Fritz 11 for free. Fritz 11 works very well with 1 CPU. Also, ...
5
votes
1answer
76 views

Clarifications on the number of nodes explored per seconds

I am trying to understand exactly what is meant when a chess engine is reporting a number of explored nodes per second. For example, on a single thread, Stockfish is reporting about 1.5 million nodes ...
9
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3answers
3k views

Where can you play against AlphaZero?

I have read a few articles about the game between Stockfish and AlphaZero. But is there a place where anyone can play against AlphaZero?
19
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3answers
4k views

Is it more helpful to play with a titled player than to play with a chess engine?

I can choose to hire a titled player to play with me; at the same time, playing with the computer is usually free and more flexible. As far as improving one's chess skill is concerned, is there more ...
-3
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2answers
120 views

What do you think will happen when chess gets solved? [closed]

When some ultra strong computer discovers the perfect game of chess, will chess as a game die?
4
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1answer
118 views

How to compare Stockfish move preference every 1000 nodes

I would like to test how Stockfish or other Engines change their moves and evaluations as the number of nodes increases. Is there a way to run Stockfish (or another engine) and force it to output its ...
4
votes
6answers
14k views

Why don’t chess engines use Node.js?

I agree that this might look like a question that Google has the answer to, but I could not find the answer. C++ is a language that many chess engines are built on, like Stockfish and Leela Chess Zero,...
2
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1answer
129 views

Chess engine in python

Are there any open-source chess engines that are written in primarily or fully in python? For example, Stockfish is written in primarily C++.
6
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2answers
1k views

Why is this position a forced mate?

I was playing a game against one of the chess.com bots, as shown below (I was playing as white). On analysing the game afterwards, I'm aware I made a lot of mistakes, but the one I'm really confused ...
5
votes
2answers
142 views

How to evaluate whether a position will result in a draw vs a decisive outcome?

Suppose 2 positions both have 'equal' evaluations according to the engine, but the first position has strong, easy-to-spot moves which lead to a drawn endgame, whereas the second game is extremely ...
-2
votes
1answer
68 views

"Strong ICCF players" What is your input into the game? [duplicate]

This question is directed to the experienced ICCF players. My question is basically what is the input that the human player has into the game. I was just wondering because with the use opening books, ...
6
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0answers
97 views

What is the human influence in modern correspondence chess? [duplicate]

On most websites, such as chess.com and lichess.org, computers aren't allowed, but when playing under ICCF rules engines are allowed. With the increase in strength of engines especially from the ...
7
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2answers
531 views

Why don't engines show explicitly that a certain move takes to a threefold repetition (instead of just showing 0.00)?

I get that from the point of view of the engine there's no difference; equal is equal. But for a human analyzing with an engine, I find quite important to note that a move takes to a balanced position ...
4
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2answers
399 views

Engine's 2nd best move

Especially for checking studies (maybe also for teaching), it would be helpful to have an engine finding the second best move and assess it (or even give refutations of all alternatives). For a ...
2
votes
1answer
145 views

Bitboard chess engine design

What are the best approaches to designing a chess engine? What classes/structures should it have? How are they connected to each other? I'm building a chess engine but I often find myself overwhelmed. ...
7
votes
3answers
353 views

What do chess engine evaluation scores (+1.3, -3.2) really mean?

I know that chess engine evaluations like +1.3 intuitively mean that White is evaluated to have an advantage equivalent to 1.3 pawns of material, or that -3.2 means that Black is evaluated to have an ...
18
votes
5answers
5k views

Making my own chess engine for a college project

I'm starting my college project to build my own chess engine. The problem is that I have no clue where to start or what to read. I found videos on YouTube but I don't want to be a copycat. I want to ...
4
votes
1answer
160 views

Move generation for sliding pieces and Hyperbola Quintessence

I'm working on a bitboard-based chess engine at the moment and I have managed to generate pseudo-legal moves for knights, kings and pawns. However, I'm still trying to wrap my head around sliding ...
0
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1answer
67 views

Search function for chess engines

I'm creating a bitboard based chess engine in c++ and I'm trying to write the search function. It currently looks something like this double search(Position& pos, int depth, double alpha, double ...
1
vote
1answer
67 views

Evaluation function in a bitboard based chess engine

How do you go about writing an evaluation function for a bitboard bases chess engine? I want to start of simple and only evaluate based on piece value, and where the pieces stand. For example a knight ...
2
votes
1answer
180 views

What is the longest known 7-piece checkmate?

What is the longest known 7-piece checkmate?
0
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1answer
71 views

Is it possible to manually input a command to Arena Chess GUI?

I want to manually input a single UCI command into my modded version of Stockfish to access my added functionality(a chat feature) and the incredibly useful eval command and then get the output. I'm ...
2
votes
0answers
102 views

Understanding Null move pruning

I have trouble understanding null move pruning. I understand the concept of a free move for the side that just played a move, but what I don't understand is the code part: int score = -negamax(-beta,-...
1
vote
0answers
85 views

Is this a possibly faster way to find pinned pieces using magic hash?

Okay so this is something that I came up with while working on my own engine, but I am not sure if anyone has ever tried. Basically I am using a separate set of magic hashed longs to store pieces and ...
1
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0answers
173 views

Magic bitboards not speeding up my engine

I'm new to writing chess engines but just recently finished my first program. It ran slowly however so I switched over to bitboards, and now to magic bitboards. I used the chess programming wiki a lot....
5
votes
1answer
1k views

Is there a resource for chess puzzles that are altered just enough to discourage easy engine use to solve?

I'm hosting a chess night and would like to post a few wallchart puzzles but would like to discourage folks from secretly whipping out their phone's chess app/engine and scoring points unfairly. For ...
1
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0answers
107 views

Clear Stockfish hash table after every move conveniently

When analyzing a game with Stockfish I sometimes find it confusing that evaluation of a given position changes depending on what positions I had analyzed previously. I understand that this is because ...
1
vote
3answers
313 views

How good is 1. e4 c5 move for black? Why does Stockfish play it?

I've been running some engine vs engine games out of boredom and noticed Stockfish, when playing as black, 90% of the time played c7-c5 on white's e4. I've never actually seen a human play this, in ...
8
votes
1answer
172 views

Reanalyzing old chess books

Computers were demolishing analyses way before they became God (see e.g. here), but latest at ELO 3000 or so it became humiliating. Do you know instances of chess books explicitly rewritten years ...
1
vote
0answers
100 views

Why is futility pruning causing an Elo drop in my engine?

I'm getting weird results when introducing futility pruning into Blunder. On the one hand, I'm getting a pretty sizeable reduction in nodes, and I'm searching a full ply deeper for some positions (e.g....
23
votes
3answers
9k views

Why does chess.com consider this promotion a blunder?

I've just played a game on Chess.com, and I'm surprised that the engine considers a promotion that I made a huge blunder. Like, my position was rated -62.8 (basically a won game), and after I promoted ...
3
votes
1answer
184 views

Computer repeating moves?

Where I observed it [FEN "3k3r/pp1n2R1/2p1bp1p/6p1/2PP1p2/1PBB3P/P4KP1/8 w KQkq - 0 1"] 1.d5 cxd5 2.cxd5 Bxd5 3.Bf5 Nb6 4.Bxf6+ Ke8 5.Bg6+ Kf8 6.Re7 Bc6 7.Rf7+ Kg8 I was using Stockfish/...
2
votes
1answer
251 views

is The following position a win or a draw?

In an engine match Leela zero vs Komodo 14 Dragon at hyper-long time 6 hours each engine) in an Alekhine Defense game, Modern variation, the following rook endgame appeared on the board. [FEN "...
-1
votes
1answer
114 views

Most difficult puzzles for chess engines [duplicate]

I know this type of question has been asked a few times but each of the puzzles in the answers are solved by engines. For example Plaskett’s puzzle and other common ones such as Mitrofanov deflection ...
4
votes
2answers
204 views

Techniques used for Stockfish engine selectivity

Example puzzle (I'm sure there are numerous that fit this bill): [FEN "rnbq3r/pppp4/3b1pkp/5p2/2BP4/4P3/PPP2PPP/RN1QK2R w KQ - 0 1"] [Site "Earth"] [White ""] 1. Qh5+ ...
1
vote
1answer
423 views

How do you make NNUE neural network for the newest Stockfish chess engine?

How can I make, for example, Stockfish 13 or 14 with a NNUE neural network? What is the precise procedure for making a NNUE neural network for some chess engine? I noticed that lichess.org uses ...
3
votes
1answer
138 views

Is there a way to classify a chess position using algorithms and data science?

Given a position, is there a way we can classify a it, such as if whether there is a pin, fork, or trap, or a mate a mate in 2 or 3? If it is possible, what would be a better approach, an algorithmic ...
1
vote
1answer
50 views

Python-chess : How to make infinite analysis in multiPV mode?

I need to run infinite analysis in multiPV mode. How to do it right? My code doesn't work. original_fen = "7k/1b1r1pp1/3Bp1np/1p2P1q1/8/1PQB2P1/2R2P1P/6K1 b - - 3 23" original_board = chess....
3
votes
0answers
45 views

Setting up Stockfish for Droidfish

I would like to set up Stockfish for the android app Droidfish. How do I set up a server for a Windows machine (my linux machine is too weak) using SF13?
3
votes
0answers
148 views

How engines accomplish calculation speeds of 1000kN/s per Core and above?

I am developing a chess engine to improve my Cpp. It works, which means it generates legal moves and it can play them out. I optimized a bit and now achieve ~20k N / s, which is way better than my ...
2
votes
1answer
190 views

How do I get Stockfish to write its analysis to a file using a batch file on Windows?

I can get this to work in a Windows Command Prompt window as follows: stockfish_14_x64_modern.exe uci ucinewgame position fen rnb1kbnr/ppp1pppp/8/3q4/8/8/PPPP1PPP/RNBQKBNR w KQkq - 0 1 go depth 17 ...
1
vote
1answer
57 views

Example of "lowerbound" and "upperbound" in the UCI protocol

I am having trouble understanding how "upperbound` and "lowerbound" come into play in the UCI protocol. The spec says: lowerbound: the score is just a lower bound. upperbound: the ...

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