So say my queen is pinned in front of my king by the opponents rook. However if I move my queen to check their king it is certain checkmate, is that legal? I'm not sure because I'm intentionally endangering my king to be taken on the next move, but technically there won't be a next move since I checkmate my opponent.
The rules are clear. A move that puts your king in check is an illegal move (I'll leave it to you to find the reference; you might find the other rules helpful to review once you get there).
You cannot checkmate your opponent's king (or accomplish anything else) with an illegal move. Once you make an illegal move on the board, the following things happen:
- The position is restored to the position in effect before the illegal move is made.
- You get penalized for an illegal move. For the 1st and 2nd offenses, this results in your opponent's being awarded an extra 2 minutes on his clock. For the 3rd offense, the normal penalty is forfeit of the game.
Nice try, though.
Think of it this way:
Check mate is where nothing the opponent can do will save them from taking you taking their king on the next turn, so even if by putting their king in checkmate, you expose your own king, they can take your king before you can take theirs.
There is NO circumstance in which your actions put your own king into check without an opponent making a move.
Basically if you are confused about pin/checkmate rule, just play the game out until one king is captured.
You move you Q to threat taking his king in your NEXT move. Unfortunately it's now his move and he takes your K first.
On the other hand, if you use your other piece to attack so that his K has to move into your pinned Q's firing range, you can capture (not threat to capture) his K with your Q before he can capture your K. Or in standard chess rule, he is checkmated.
Official chess rules by FIDE
Rule 3.9 is as follows:
3.9 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 that square because they would then leave or place their own king in check. No piece can be moved that will either expose the king of the same colour to check or leave that king in check.
In standard chess, no, you cannot move into, nor make a move that puts your king in, check.
I noticed this is tagged chess-variants, so I will add that the rules for speed/blitz chess may be slightly different, in terms of penalties. In addition, in casual blitz games, that may be acceptable.
Well, your queen is pinned in front of king by an enemy rook? I can show you a few examples to show when you can and cannot move your pinned queen to deliver checkmate.
In this scenario, the pinned white queen cannot checkmate the black king by moving either to a4 or g4, as that would expose it’s own king to check, an illegal move. However, it can capture the black rook while still being pinned, simultaneously unnpinning itself, a legal move if it does not put the king in check, and checkmating.
[FEN "4k3/4r3/8/8/1B6/8/4Q3/3RKR2 b KQ - 0 1"]
In this second example, it is illegal for the pinned white queen to move to f1 to deliver mate, as that would expose the king to check, an illlegal move.
[FEN "1k6/4r3/B3Q3/1N2K3/8/8/8/8 b - - 0 1"]
Interestingly, in this case, if it is white to move, mate can not be done with the queen, as it is pinned. But if it black to move, it cannot capture the white queen as it itself is pinned. Yes, a pinning piece can be pinned.
[FEN "k1rR4/2Q5/2K5/8/8/8/8/8 b k - 0 1"]
Additionally, take a look at this hilarious case in which neither side’s queen could move to deliver a checkmate, as both are pinned.
[FEN "6k1/6q1/6R1/8/8/1r6/1Q6/1K6 b - - 0 1"]
Here is an extreme example of TWO pinned queens not being able to deliver mate due to that being an illegal move.
[FEN "2r5/2Q5/rQK5/8/8/5N1B/8/7k w - - 0 1"]
And here is the reverse where both pinned queens can deliver mate by capturing the pinning piece.
[FEN "k1r5/2Q5/rQK5/8/8/8/8/8 w k - 0 1"]
Lastly, here is an utmost absurd showing with SIX (definitely the limit) queens (four if you don’t count the ones pinned by a bishop, based upon this questions terms) not being able to deliver checkmate due to being pinned. The queens on d3, d4, e5, d3, and f4 cannot deliver mate at all, while the e3 queen cannot move to c1, d2, or f2 to deliver checkmate. However, it is legal for it to unpin itself and deliver checkmate at the same time by capturing the e2 rook.
[FEN "8/8/4r3/4Q3/2rQKQr1/3QQQ2/2b1r1b1/4k3 w - - 0 1"]
To gain an even wilder understanding of how pins work, here is the Immortal Pin Game, where black is checkmated with three pins on his king.
[Title "Edinburgh Club Championship, 1981,Geoff Chandler-Richard Kynoch, 1-0"] [FEN ""] 1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nc3 e6 5. g4 Bg6 6. Nge2 c5 7. Be3 Nc6 8. dxc5 Nxe5 9. Nd4 Rc8 10. Bb5+ Nc6 11. Qe2 Nf612. O-O-O Be7 13. h4 h5 14. f3 Nd7 15. gxh5 Rxh5 16. Rhg1 Nxd4 17. Bxd4 Qc7 18. Rxg6 fxg6 19. Qxe6 Rf5 20. Nxd5 Qd8 21. Qxg6+ Rf7 22. Re1 Kf8 23. Qh7 Ke8 24. Qg8+ Rf8 25. Qxg7 Rf7 26. Qg8+ Rf8 27. Nf6# 1-0