Allumwandlung is a chess problem

Chess problem

A chess problem, also called a chess composition, is a puzzle set by somebody using chess pieces on a chess board, that presents the solver with a particular task to be achieved. For instance, a position might be given with the instruction that White is to move first, and checkmate Black in two...

 where, at some stage in the solution, the pawn

Pawn (chess)

The pawn is the most numerous and weakest piece in the game of chess, historically representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the rank immediately in front of the other pieces...

 (or sometimes pawns) is promoted variously to a knight

Knight (chess)

The knight is a piece in the game of chess, representing a knight . It is normally represented by a horse's head and neck. Each player starts with two knights, which begin on the row closest to the player, one square from the corner...

, bishop

Bishop (chess)

A bishop is a piece in the board game of chess. Each player begins the game with two bishops. One starts between the king's knight and the king, the other between the queen's knight and the queen...

, rook

Rook (chess)

A rook is a piece in the strategy board game of chess. Formerly the piece was called the castle, tower, marquess, rector, and comes...

 and queen

Queen (chess)

The queen is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally, or diagonally. Each player starts the game with one queen, placed in the middle of the first rank next to the king. With the chessboard oriented correctly, the white queen starts...

.

At right is a chess problem composed by Niels Høeg and first published in 1905. White to move and mate in three. The key move (white's first move) is 1.f7, and depending on how black defends, white promotes to either a queen, a rook, a bishop or a knight on move two. The lines are:

1... e4 2. f8Q any 3. Qe7 mate (or Qf6 mate)

1... Kd6 2. f8Q Kc6 3. Qc5 mate

1... exf4 2. f8R Kd6 3. Rf6 mate

1... exd4 2. f8B Kf6 3. Ra6 mate

1... Kf6 2. f8N exd4 3. Rf7 mate

The importance of white's underpromotions can be understood by considering what happens if he promotes to a queen no matter what black plays: after 1... exf4 or 1... exd4 2. f8Q is stalemate

Stalemate

Stalemate is a situation in chess where the player whose turn it is to move is not in check but has no legal moves. A stalemate ends the game in a draw. Stalemate is covered in the rules of chess....

, while following 1... Kf6 2. f8Q Kxg6 there is no mate.

External links

• A selection of Allumwandlung problems, mostly fairy
  Fairy chess piece
  A fairy chess piece or unorthodox chess piece is a piece analogous to a chess piece. It is not used in conventional chess, but is used in certain chess variants and some chess problems...