# Questions tagged [problems]

Chess problems consist of a board position and a task. Most ask for a line of play that mates black in a set amount of moves, or a combination that results in a winning position. Many other types exist, including, but not limited to, construction tasks for various positions and proof games that have numerous goals, selfmates, helpmates, and retrograde analysis. Tournaments and championships exist for composing of original problems and for speed-solving.

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### Longest sequence of mutually forced moves

In this position, the black move 1. ... Qc3 results in two consecutive forced moves, Kxc3 and Ke7: 2rkr3/2p5/2q5/8/8/8/3KP3/3R4 b - - 0 1 1... Qc3 2. Kxc3 Ke7 What is the longest sequence of ...
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### What is the theoretical limit for the number of consecutive checks?

The known record for the longest sequence of consecutive checks (i.e. white checks, then black checks on the next move, white checks next, and so on) in a legal position without promoted pieces, is 37....
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### Maximum possible movement in a turn

I've read that for any position, there are on average approximately 35 possible moves. But what's the maximum number of possible moves for a position?
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### What is the shortest possible game with 18 queens?

This question demonstrates a game in which all 16 pawns promote for a total of 18 queens on the board. It takes 80 moves... What is the shortest sequence of moves that achieves this goal?
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### What is the longest proven forced win (including 50 & 75 move rules)?

What is the longest (currently discovered) number of moves for a forced mate position where players will use both the 50-move draw rule and the 3-fold repetition rule if it will help them avoid losing?...
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### Solvable studies that computers fail to crack

Are there chess studies that require an outside of the box thinking that goes beyond the concrete calculation capabilities of today's engines (e.g. Stockfish)? I have sometimes seen certain endgames ...
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### A mysterious mate in one

Here's a question that's a little off the usual format, but problem questions like this have been done before and are on topic, so here we go! Question: Can you find the mysterious mate in one? The ...
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### Fastest King vs King endgame

What is the fastest possible game that ends in a King vs King endgame? Please post a game and tell me the number of half-moves you've achieved. By some simple logic, I can prove that this number is ...
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### Mutual Stalemate

You are required to find position such that: 1) Any move made by White or Black leads to stalemate for both sides immediately. 2) The position can be reached from the starting position of a chess ...
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### Is it possible to have a double self-smothered stalemate?

I came up with this rather amusing and bizarre stalemate where Black stalemates itself by self-smothering. [FEN "8/8/8/8/8/3p4/pp6/krb1K3 b - - 0 1"] 1...d2+?? 2. Kd1 The peculiar feature of ...
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### What is the highest number of pieces from one side that can be involved in a checkmate?

What is the highest number of pieces from one side that can be involved in a checkmate? "Involved in a checkmate" is defined below. A non-king piece is involved in a checkmate 'if removing ...
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### Longest sequence of moves where number of available moves increases

White has 20 available moves at the start of the game. After 1.a4 e5, white has 21 available moves. (The rook has gained 2 moves, while the pawn has lost 1). What is the longest sequence of moves ...
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### When was it possible for a player's king to be attacked by 3 of the opponent's pieces?

According to the current FIDE Laws of Chess: 3.9.1 The king is said to be 'in check' if it is attacked by one or more of the opponent's pieces, even if such pieces are constrained from moving to ...
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### Stalemate situation with all pieces on the board

Suppose all the pieces are on the board. Does there exist a position such that A) one of the players can't make any move (a stalemate)? B) neither player can make any move (a double stalemate)?
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### Maximum number of queens possible

I was thinking about what the maximum number of queens can be on the board after only legal moves. The theoretical upper bound would be 18, the original 2 queens plus 16 promoted pawns. However, to ...
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### Fastest possible checkmate by en passant

En passant is somewhat of a rare move in chess. Checkmating by en passant, however, is an even rarer occurrence. But suppose both sides had the same goal to help cause a checkmate to their opponent ...
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### Maximum number of pieces on board in dead position

It is possible in a chess game to have a dead position in which both players have all eight pawns, one bishop, and a king--20 pieces total. If the two players' pawns are interlocked in "zig-zag" ...
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### Positions that stump engines

Chess engines are so strong that it is becoming increasingly hard to find positions that they are demonstrably evaluating incorrectly. I'm interested in collecting examples—if there are any—of ...
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### What is the maximum number of passed pawns in a position?

Something I have wondered about recently is the maximum number of passed pawns that is theoretically possible. What is the answer, and the fastest way to achieve that result?
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### Position with the most (or many) distinct refutations?

I'm looking for a chess position, hopefully not too contrived, in which it's Black's turn, he has several moves, but each one is refuted by a mate by White. I know I could take any mate-in-two ...
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### Problem: reconstruct the game

In the following position, each side has made exactly 4 moves (8 in total). [fen "rnbqkbnr/pp3ppp/2p1p3/8/4P3/8/PPPP1PPP/RNBQK1NR w KQkq - 0 1"] I need to find what these moves were.
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### Legal positions with one color to move only?

Most positions in chess can be reached with both black or white to move. Some positions are only legal with one color to move. One such position is the starting position, which famously can't be ...
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### Longest sequence of moves where white's number of available moves decreases

An easier version of this White has 20 available moves at the start of the game (from the standard position). After 1.h3 h5, white has 19 available moves. (The h pawn has lost the ability to move two ...
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### How many steps to mate the only king with all pieces?

Suppose Black has only one king in its initial place and White has all 16 pieces in their initial places. How many steps does it take to ensure a checkmate? And what are all solutions? Now that White ...
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### The quickest mate in n

Obviously inspired by the analogous selfmate question. (Helpmate would also be possible in principle, but looks a bit silly.) Thus, 1.f3 e5 2.g4 allows Black a #1, and 1.f3 e5 2.h3 a #2. 1.f4 e5 2....
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### Searching for a "where is the black king" problem

Sometime ago, a friend showed me a position where he had the Black king removed. The goal was to find where is the Black king using some pretty weird reasoning. There were only a few pieces on the ...
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### The quickest selfmate in 1

How quickly can a legal game reach a position where one side must give checkmate? This is in effect Evergalo's reading (see his (now deleted) answer) of Rewan Demontay's Question 33154; that question ...
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### How fast can checkmate occur by just moving the king?

How short can a game be in which (after the first move) one player moves only their king, and yet checkmates their opponent? This is assuming that the players cooperate, i.e. this is a kind of "...
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### What move requires the greatest number of moves before it could be played in a game?

The move e2e4 could be played on move 1. (One half-move) The move e7xd6 could be played no earlier than by black on move 3 (6 half-moves). What move(s) has the latest "earliest possible move it ...
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### From the start of the game what is the longest possible series of consecutive white moves where white can do those moves no matter what black does?

From the start of the game what is the longest possible series of consecutive white moves where white can do those moves no matter what black does? So I want the longest list of moves white can do ...
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### Another Unusual Mate in One

Here is another mate-in-one of my own i.e. a not quite usual one... [title "Mate in one"] [FEN "3b4/R3P3/2kPR1n1/P1p1n3/4K1p1/2Nr4/5p2/1b6 w KQkq - 0 1"] Imagine, you ...
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### Is there any position where not promoting (illegally) would be the best move?

Is there any position, where moving a pawn to last rank but not promoting it to any piece would be the best move? By the way, I know this is an illegal move. Assume it is legal. Edit: Now we have a ...
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### What is the longest known sequence of forced moves leading to a checkmate for one side?

By forced move, it is meant that the player has only one legal move. [fen "7k/q5Q1/p4PPK/6PP/8/5P2/8/8 b - - 0 1"] 1... Qxg7+ 2. fxg7+ Kg8 3. f4 a5 4. f5 a4 5. f6 a3 6. f7# Above is an example with ...
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### Is there a double-forced mate position?

A usual forced mate position is where the winning player can play in a way that ensures checkmate, no matter what (legal) moves the opponent makes (unless the game ends due to a non-play reason, i.e. ...
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### Beautiful retrograde analysis problem by Alexsey A. Troitsky

I saw this beautiful, subtle & accessible problem a couple of days ago, and wanted to share it with you folks. (It's by the ground-breaking endgame theorist who e.g. invented the "Troitsky line" ...
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### Giving moves as odds, what's the least number of moves by White which forces checkmate by the time it's Black's turn?

If one player (Black) gives another player (White) odds of x moves, stipulating that White must not move any man beyond his fourth rank until Black has made one move, what's the smallest value for "x" ...
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### Which piece combinations can mate a lone king without being aided by the attacking king?

Clearly not a practical question since the king can and should be used in the endgame, but I was curious if anyone has done a comprehensive analysis of which combinations of pieces (including some ...
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### White to force the end of the game in two moves

I found this hilarious problem and hope people will have fun solving it: Niels Hoeg, Skakbladet 1907 [FEN "8/8/6p1/5pP1/5P1K/5PpP/4p2p/2Q2Bkr w - - 0 1"] White to end the game in two moves. In ...
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### Identify a problem where a potentially winning move draws because of the 50 move rule

I'm trying to recall a particular chess problem. It's related to retrograde analysis. All what I can remember is this: it's an endgame where there is only one way to reach the position, and during ...
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### Is there a computer program that generates quality chess problems?

Is there a chess engine that automatically generates quality chess problems. For example I will input 3 - it produces a mate in 3 problem. But the problem shouldn't be so obvious that one can solve in ...
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### Position where neither player can force a win and neither player can force a draw

One sometimes sees the claim that in every chess position, either White has a forced win, or Black has a forced win, or both players can force a draw. While this claim is "morally" correct, ...
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### How to solve this puzzle of Martin Gardner?

Martin Gardner mentioned the following "chess" problem in his column, Mathematical Games, for Scientific American (he got it from Smullyan, who learned about it from a high school math ...
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### Difference between chess puzzle and chess problem in this episode of The Queen's Gambit?

While a chess puzzle is any puzzle involving aspects of chess, a chess problem is an orthodox puzzle in which one must play and win or draw a game, starting with a certain composition of pieces on the ...
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### Chess problem - don't understand the solution

Black to move: [fen "4rbk1/pp3pp1/1nq4p/8/1PP5/P3N1P1/Q2BrP1P/3R1RK1 b - - 0 1"] I've tried to solve this chess problem - black to move, find the best move. I couldn't work it out so I checked the ...
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### Studies that have been cooked by computers

A study is unlike a regular chess problem. Instead of "mate in 3" (for instance), a study's instructions are something like "White to draw" (for instance). What this means is to find a line of play ...
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### Mate in One the Missing King

The post "A mysterious mate in one" made me think of one of my last problems which is also a Mate-in-One with no black King: [Title "White to move and mate in one"] [FEN &...
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### Helpmate of arbitrary length

One of the FIDE rules states that if someone's flag falls, and there exists a legal sequence of moves such that the other player mates the first player, then the position is a win for the second ...
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### Uniquely Satisfying Puzzle

Here is a fun puzzle I found some time ago. It was created by Karl Fabel in 1952 and published in Rätselstunde. Goal [title "White to move and NOT checkmate in one!"] [fen "B5KR/1r5B/6R1/2b1p1p1/...
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