72
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 ...
- 25k
61
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 ...
- 6,640
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 ...
- 17.8k
54
votes
Accepted
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 ...
- 16.7k
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 ...
- 651
52
votes
Accepted
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 ...
- 28.7k
49
votes
Accepted
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 ...
- 17.8k
48
votes
Accepted
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 ...
- 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 ...
- 20.9k
42
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 ...
- 12k
41
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. ...
- 17.8k
38
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 ...
- 4,415
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/...
- 8,028
35
votes
Accepted
Is there a position with the stupidest possible move?
Every single legal move from White checkmates—except the extremely stupid Bd7. There are 12 (discovered) checkmates with the rook on g2 alone. After the stupid move, Black is forced to give checkmate ...
- 6,287
31
votes
Accepted
Zugzwang where the side to move must be mated in exactly 2 moves
As Laska suggested, I was able to find it
in my 2001 files of correspondence with Richard Stanley:
[Title "Whoever moves must get mated in 2 moves (NDE 2001)"]
[FEN "BKQQ4/pPPP4/rbkp4/...
- 8,314
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
- 8,314
27
votes
Accepted
How many queens can check a king without it being checkmate (with no other pieces on the board)?
The question asks for "no other pieces on the board" apart from white queens and a black king. So the other answers looking for legal positions seem to be missing the point.
If we're looking ...
- 1,603
27
votes
Can a unique position be deduced if pieces are replaced by checkers (can see piece color but not type)
Maximum:
[FEN "PppppppP/pppppppp/8/8/8/8/PPPPPPPP/pPPPPPPp w KQkq - 0 1"]
The board must be right side up because the armies cannot switch sides
without some capturing.
Given this, all the ...
- 8,314
26
votes
Accepted
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 ...
- 100k
26
votes
Basic "mate in one move" puzzle - what am I missing?
You are absolutely right! The black king can move to d8 and e7 and then there's no follow up mate. Most probably there's a white queen/bishop on h4 to prevent the black king from escaping (which is ...
- 1,875
25
votes
Accepted
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 ...
- 20.9k
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 ...
- 863
24
votes
Accepted
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 ...
- 4,415
23
votes
Accepted
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 ...
- 17.8k
23
votes
Is there a double-forced mate position?
Indeed, there are many possible positions in which all mates are forced on the first ply. Since you ask not for that, I shall provide examples with more than one move by both sides.
Here is the known, ...
- 17.8k
23
votes
Accepted
Is it possible to create a board position where White must make the move that leads to stalemating Black to avoid Black stalemating White?
Here is a slightly less cluttered version:
[FEN "7k/6p1/6PP/8/8/1p6/pP6/K7 w - - 0 1"]
- 4,117
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. ...
- 671
22
votes
Accepted
Another Unusual Mate in One
There are two checkmates per orientation:
[title "Mate in one"]
[FEN "3b4/R3P3/2kPR1n1/P1p1n3/4K1p1/2Nr4/5p2/1b6 w KQkq - 0 1"]
1. exd8=N#
and
[title "Mate in ...
- 100k
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