My Mate in 3 puzzles

Mate in 3. There is only one move by White to trigger this Mate in 3. However, there are several solutions depending on Black's responses. I've chosen one here. Each move by White is the only move toward checkmate.

Don't move the same piece twice.

Don't move the same piece twice.

But 3. Qxh7 is correct too

No. In this puzzle you can't move the same Queen twice. There is a solution to checkmate with 3. Qxh7, but that requires two moves by the same Queen. Firstly, one of the Queens must move to the same diagonal as the White Bishop in order to capture and checkmate with 3. Qxh7#.

that was fun

thanks for that

This is a Mate in 4.

Too easy. This is only an M2 and easy to see the solution since it started with a check followed by the checkmate move.

[Edit] Sorry, it is an M3 if Black makes the best moves.

Don't move the same piece twice. [Edit] Subsequent to this puzzle being posted with what I thought was the only 3-piece combo solution, jetoba found a second 3-piece combo solution which involves Re6 and Re1. Please ignore that alternative solution for this puzzle.

Note that your last puzzle is unsolvable. For instance, after 1. Qxc7 Rf7 you can't mate in 3 moves unless you play the queen twice against the instructions.

Thanks for trying out my puzzle. The reason that I instructed "Don't move the same piece twice" is that many solutions exist involving the White Queen and Rook in combination where the Queen is moved twice or the Rook is moved twice. You discovered one of those lines but there are others. Since choosing any of those lines makes the puzzle unsolvable, I chose the only line involving three pieces in combination.  The way I would solve this puzzle is to ask how can the White Rook threaten the Black King in one move? By moving Re8. But then the Black Rook would block with Rf8 forcing a second move by the White Rook to trade Rooks. So, the White Rook can't move first and the Black Rook must be captured. The White Queen could move first and capture the Black Rook on f6 with Qxf6. But then checkmate can only be achieved with another two moves by the White Queen or two moves by the White Rook. These lines make the puzzle unsolvable because two solutions are possible. The puzzle only works if there is only one possible solution. Therefore, the first move must be Qxc7, allowing the White Bishop to remove the problematic Rook on f6 on the next move as long as the Black Rook stays on f6 (which it does). Perhaps you think 1.... Rf7 is a more natural move than creating a passed pawn with 1.... cxd5. Is that the issue you have with the puzzle?

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Not sure I got that. The responsibility for having just one solution lies with the puzzle maker and not with the black or white side. The black side is supposed to resist the white side and not help him in fulfilling the assignment. "Natural moves" are never an issue in puzzles, there are only "right" and "wrong" moves. In fact, your condition of having every piece move just once is an extremely "unnatural" condition in a chess game but it could make certain puzzles a bit more interesting. It fails here because you don't stick with your own condition.

The puzzle only works if the Black Rook on f6 stays there after 1. Qxc7. You may be right that leaving the Black Rook on f6 is wrong because 1. ...cxd5 is a computer move. It's not a human move. However, I didn't think that mattered for a puzzle which can only be solved by not anticipating Black's first move but responding to each of Black's moves as they occur. I said in a previous post that I wouldn't include a blunder in the solution and I didn't. But in hindsight, the computer move 1. ...cxd5 is too unnatural although technically it's not a blunder. I'll try and keep unnatural computer moves out of my puzzles in future. Thanks again for your good feedback.