70 votes
Accepted

Can you solve this unique chess problem of white's two queens vs black's six rooks?

It's checkmate in 20 moves. White's queens circle around the board giving checks, and Black interposes horizontally/vertically moving pieces. Black only has one choice because the other piece is ...
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  • 23.8k
58 votes

Stalemate situation with all pieces on the board

Here is an example of a 12-move game after which White (to move) is stalemated. All 32 units (pieces and pawns) are still on the board. The original version of this concept game was created by Charles ...
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  • 5,560
56 votes

How can I prevent checkmate in this position?

Initial Analysis White is clearly in a dire situation, since Black is threatening mate in one on either h7 or h8 if White doesn't do anything. But the White king can't move nor can White get rid of ...
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54 votes

Can all 64 squares be attacked or defended by the eight pieces?

If the two bishops travel on the same color squares, then all 64 squares can be covered by the eight pieces. However, if the bishops must travel on opposite colors, then the maximum number of squares ...
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53 votes
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How fast can checkmate occur by just moving the king?

Here is a starter solution in 7 moves. Can we do better? [FEN ""] 1.g3 e5 2.Bh3 Ke7 3.Bxd7 Kxd7 4.Kf1 Ke7 5. Kg2 Ke6 6.Kh3 Kf6+ 7.Kh4 Kg6# If this is best, interestingly, the play is ...
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  • 12.8k
51 votes
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How is this position possible in a normal game of chess?

Double check is only possible by using discovered check. So either the rook check or the bishop check was discovered by moving something in between on the previous move. I don't see how that's ...
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  • 25.8k
47 votes

How fast can checkmate occur by just moving the king?

It's impossible to checkmate faster than 7 turns (handicap on black) or 8 turns (handicap on white). Proof by elimination I'm going to argue from the perspective that white is helping and black is ...
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  • 571
46 votes

Why underpromote in this KNNP-KR endgame?

If you promote to a queen with 1. b8Q, black has: 1...Re2+ 2. Kd1 Rb2 attacking the queen and hinting at mate with Rb1++. If white takes the rook 3. Qxb2 it is stalemate. Because of the mate ...
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  • 20.3k
43 votes
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A mysterious mate in one

Looking at the problem as if the black King is currently invisible...
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41 votes

Endgame problem: How to avoid stalemate and win?

It's quite a fun problem to think about, before getting to the calculation of long variations, try to first spot the key idea needed to crack the problem. Here are the first observations that come to ...
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  • 11.8k
40 votes
Accepted

Is the position in this trick question reachable?

Even though the board is upside down, the position is still easily legal. [FEN ""] [startply "86"] [StartFlipped "1"] 1. a4 h5 2. g4 h4 3. Bg2 Rh5 4. gxh5 h3 5. h6 e5 6. ...
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39 votes

Please help solve this endgame problem posed by a friend

White is one tempo short of catching the pawn - if White could make two moves immediately it would be a draw as white would just take the black pawn. But they can't, so white has to find a threat ...
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  • 4,031
37 votes
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When was it possible for a player's king to be attacked by 3 of the opponent's pieces?

In my thread on the English Chess Forum, which seemed to make the world go crazy on the subject, I gave all the major and minor events in the history of the “legal” triple check that my extensive ...
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35 votes

White to play and checkmate in two moves

Use the fact that the rook is pinned, and that the king has few squares left; I'm thinking that 1.Rd8 Kd3 (only possible move) 2.Nc5# should be the solution. [White "NN"] [Black "NN"] [FEN "7R/1B1N4/...
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  • 7,322
32 votes

Longest sequence of mutually forced moves

Assuming you allow promoted material (since you didn't say anything :-), this (on Page 13 of the PDF) is the (unfortunately, extremely unknown) finite record since ages. It shows the record for the ...
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30 votes
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What is the solution to this mate in 2 puzzle?

It is a nice little puzzle: 3k4/3P4/3Q4/8/8/8/8/4K3 w - - 3 13 1. Qd5 Kc7/Ke7 2. d8=Q# 1-0
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  • 23.8k
29 votes

What moves solve this mate in 2?

White to play checkmates in 2 with 1 d4+! exd3 e.p. 2 Qbf4#. Black to play cannot checkmate in 2 but should win after Bxf7. 7r/1p3Q1p/2q5/3bk3/1Q2p3/2P5/r2P2PP/2KR4 w - - 0 1 1. d4+! exd3 2. Qbf4
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28 votes

Is there any position where not promoting(illegally) would be the best move?

Here is an example: [fen "8/4P3/8/4p1p1/2p3Pp/p4p1K/k1p2P1P/8 w - - 0 1"] 1. e8 leads to stalemate next move, while all legal promotions lose to 1... c1=Q followed by 2... Qf1#.
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26 votes

What is the highest number of different mates in 1 you can have in one (legal) position?

[FEN "1B1Q1Q2/2R5/pQ4QN/RB2k3/1Q5Q/N4Q2/K2Q4/6Q1 w - - 0 1 "] 105 mates — Nenad Petrovic, Sahovski Vjesnika 1947 (Chess Problem Database) In this position any check is mate. There are 3 knight mates ...
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  • 3,226
26 votes
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Can White avoid a loss in this endgame study by Lazar?

The first half of white's move is forced - d8. Then white has a choice of knight, bishop, rook or queen. Black has two threats which white must parry to get a draw. The first is to play Bf4 and then ...
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  • 74.6k
25 votes
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What is the least number of knights needed to cover the entire board?

Depending on whether occupied squares need to be covered as well, the number is: [Title " 12 knights, Without Covering Occupied Squares"] [FEN "8/5N2/1NN1NN2/2N5/5N2/2NN1NN1/2N5/8 w - - 0 1"] [Title ...
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  • 20.3k
25 votes
Accepted

Can you solve this queen + 3 pawns vs bishop + 3 pawns chess problem?

If White can get the Black king to the first rank, then it will not be fast enough to catch the g-pawn from promoting. White starts by playing 1. Qg5, and after 1...Kh7 2. Qf6 Kg8 3. Qh6, the White ...
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24 votes
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Can you solve this chess problem of a lone knight against numerous opposing pieces?

OK The check must come from the knight (D'uh!) The black king must be on c5 for the mate The white king must be used to cover any empty squares to the right of the black king - thus the white king ...
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  • 4,031
23 votes

Pawn Promotion Endgame Problem-White to move and mate in 1

It's probably a trick problem with a promotion to a black knight. Such promotions to the wrong colour are not allowed, and never were. In the official rules it is now specifically pointed out that ...
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23 votes
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Is the "Pawn Box" possible in standard chess?

As @BrianTowers showed, it can be done. Here’s a shorter proof game for the fun of it. [FEN ""] 1. h4 g5 2. hxg5 f5 3. g4 Nf6 4. gxf6 d6 5. gxf5 Be6 6. f4 Bb3 7. axb3 c5 8. e4 c4 9. bxc4 d5 10. cxd5 ...
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22 votes

What is the shortest number of moves from the starting position required for Black to mate White with a pawn?

4 moves, as far as I can tell. [FEN ""] 1. e3 e5 2. Ke2 Qh4 3. Kf3 d6 4. Qe2 e4# Another one: [FEN ""] 1. d3 d5 2. Kd2 e5 3. Kc3 Be6 4. Qd2 d4# And one more: [FEN ""] 1. e3 e5 2. Ke2 d5 3. Kd3 ...
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  • 3,622
22 votes
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Is there any position where not promoting(illegally) would be the best move?

The Matt Bengtson problem Prof. Elkies mentions is: [Title "Matt Bengtson, Chess Braintwisters (Burt Hochberg), no. 103. White to move & draw."] [FEN "4kn2/3p1pPp/4pPpK/6P1/8/2p5/1b6/8 w - - 0 1"]...
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  • 5,560
22 votes
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Prove that White is not allowed to castle here

This is actually a rather typical retrograde problem, just start with the most basic observations: We see that black is missing both rooks and the f8 bishop. Given black's pawn structure it's easy to ...
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  • 11.8k
22 votes

What is the theoretical maximal material difference of a dead draw which is not a stalemate?

[fen ""] 1. a4 b5 2. b4 bxa4 3. c4 c5 4. d4 cxb4 5. e4 d5 6. f4 dxc4 7. g4 e5 8. h4 exd4 9. Ba3 g5 10. Nc3 gxh4 11. Qb3 f5 12. Kf2 h3 13. Kg3 h2 14. Bd3 Qa5 15. Kh4 dxc3 16. Kg5 h5 17. Kg6 cxb3 18. ...
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