What is the missing piece on h4?

A (white or black) chess piece (or pawn) dropped on the floor accidentally. It was on h4. Can you tell me what it is?

Originally posted by Quirine
[fen]2nR3K/pk1Rp1p1/p2p4/P1p5/1Pp5/2PP2P1/4P2P/n7b--[/fen]

A (white or black) chess piece (or pawn) dropped on the floor accidentally. It was on h4. Can you tell me what it is?

Well apart from the fact that it can't be a black queen or rook I have no clue where to start on this.

Originally posted by XanthosNZ
Well apart from the fact that it can't be a black queen or rook I have no clue where to start on this.

White has made the last move: pawn c7xNd8R+. There had to be a white pawn on c7 otherwise black's last move left him in check.
It could not have been a queen or rook on d8, because the white king would have been in check since there is no way that black's last move was to play away a piece from the back rank standing between the queen and white king (it would still be there one move distance from that square). It was not a bishop on d8 either: white square bishop obviously not, wrong colour; black squared bishop has never moved from f8 because the pawns are still there on e7 and g7. So it was a knight.

That means that black promoted one pawn to a knight (the other two still on the board). With the h-pawn. The f-pawn is on c4.
Therefor, the piece on h4 is not a pawn, all 8 are identified elswhere. It is not a black knight either for the same reason. Not a black bishop (the black squared was captured on f8, and the white squared is wrong colour). It cannot be a black rook or queen because the white king was not in check. That eliminates all black pieces.

So it is a white piece. Black captured five pieces, leaving still the last one on h4: 1 axb6; 3 with the f-pawn to c4; and 1 with the h-pawn. Only possibility is from h3 to g2 to promote on g1 (all other possibilities require at least two captures). That means all captures were on white squares. Hence, the remaining piece is the white black squared bishop on h4 (thank god that is a black square).

Originally posted by Quirine
[fen]2nR3K/pk1Rp1p1/p2p4/P1p5/1Pp5/2PP2P1/4P2P/n7b--[/fen]

A (white or black) chess piece (or pawn) dropped on the floor accidentally. It was on h4. Can you tell me what it is?

From Chess Mysteries of Sherlock Holmes. The book is a great introduction to retro problems.

Originally posted by Mephisto2
White has made the last move: pawn c7xNd8R+. There had to be a white pawn on c7 otherwise black's last move left him in check.
It could not have been a queen or rook on d8, because the white king would have been in check since there is no way that black's last move was to play away a piece from the back rank standing between the queen and white king (it ...[text shortened]... he remaining piece is the white black squared bishop on h4 (thank god that is a black square).

I'm just not cut out for these problems it seems.
That's quite the solution there.

Originally posted by BigDoggProblem
From Chess Mysteries of Sherlock Holmes. The book is a great introduction to retro problems.

indeed. You only failed to mention the author: Raymond Smullyan.
Does anyone know if his other book on retro-problems "The Arabian knights" is still available?

this possition can not de reached from a normal game because how did the rook get to d7 to give check?

Originally posted by LordOfTheChessboard
this possition can not de reached from a normal game because how did the rook get to d7 to give check?

read the solution posted above. The rook on d7 must have come via f1 -> f8 (probably the piece that took the black bishop) -> d8 ->d7. The one on d8 is simply the result of white's last move, taking the black knight with a pawn and promoting to rook.

Originally posted by Mephisto2
White has made the last move: pawn c7xNd8R+. There had to be a white pawn on c7 otherwise black's last move left him in check.
It could not have been a queen or rook on d8, because the white king would have been in check since there is no way that black's last move was to play away a piece from the back rank standing between the queen and white king (it ...[text shortened]... he remaining piece is the white black squared bishop on h4 (thank god that is a black square).

I think black could also have promoted his pawn to a second black bishop, but that doesn't change the final answer.

Originally posted by Mephisto2
read the solution posted above. The rook on d7 must have come via f1 -> f8 (probably the piece that took the black bishop) -> d8 ->d7. The one on d8 is simply the result of white's last move, taking the black knight with a pawn and promoting to rook.

cool, your right, that would make it possible!😀

It seems to be impossible unless the missing piece came from a different square.

Since Black is in check from the white rook then it is black's move. With the pieces that are on the board it seems impossible how white placed his rook in the current position causing the check. perhaps a white knight or bishop are missing from the problem (e.g. a whit knight at e8 or b5 could have administered the discovered check.

obviously i didn't consider a pawn creating the discovered check. oops