Reflexmate
Encyclopedia
A reflexmate 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...

 in which white, moving first, must force black to deliver checkmate
Checkmate
Checkmate is a situation in chess in which one player's king is threatened with capture and there is no way to meet that threat. Or, simply put, the king is under direct attack and cannot avoid being captured...

 within a specified number of moves against his will - with the added condition that if either player can give checkmate, they must. If this condition applies only to Black, it is a semi-reflexmate. (Without this condition, the problem is just ordinary selfmate
Selfmate
A selfmate is a chess problem in which white, moving first, must force black to deliver checkmate within a specified number of moves against his will. Selfmates were once known as sui-mates.The problem to the right is a relatively simple example...

.)
The problem to the right is a fairly recent example, successful in the World Chess Composing Tournament despite only a single phase of play
Phase of play
Phases of play are parts of a chess problem which happen, as it were, concurrently rather than consecutively.Each problem has at least one phase: the post-key play or actual play; that is, the play after the key...

 present. It is by Štefan Sovík and is a reflexmate in two moves.

The key is 1.Qh5! and White threatens 2.Nbxc3, after which black is compelled by additional condition to mate by Rxc3#, with triple pin
Pin (chess)
In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece...

 of Rc4, Bd4 and Ne4.

There are three thematical variations with unpinnings of three pieces, but every time Black has to mate by switchback after selfpin of unpinned piece on c3:
  • 1...Qxa4 2.Rxc3 Qb5# (white move: 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...

     unpinned by 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...

     move selfpins)
  • 1...Rxc8 2.Bxc3 Rd8# (white move: 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...

     unpinned by rook move selfpins)
  • 1...Bxh5 2.Nexc3 Bg6# (white move: 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...

     unpinned by bishop move selfpins)


Further three variations result in unpinnings of white pieces, but the mates are not by switchback:
  • 1...Qd7 2.Rc6 Qxd4# (white move: unpinned rook unguards d4 and unpins queen)
  • 1...Nd5 2.Bxe3 Nf4# (white move: unpinned bishop opens d-file and blocks e3)
  • 1...Kd7 2.Bxc3 Kxc8# (white move: unpinned bishop opens d-file and selfpins on c3)


In next three variations the black pieces are unpinned and mate:
  • 1...Qc6 2.Bxb3 Qxe4# (white move: bishop unpins queen)
  • 1...Nf5 2.Rxc7 Rxd4# (white move: rook unpins rook)
  • 1...Bf7 2.Qf5 Bxc4# (white move: queen unpins bishop)


The last variation is just technical:
  • 1...Rxb1 2.Bd1 Rxd1#


The example is putting emphasis on unpinning and pinning (see motivation
Motif (chess composition)
In chess composition, a motif is basic element of a move in the consideration why the piece moves and how it supports the fulfillment of a stipulation. Any move may and often does contain multiple motifs...

) and illustrates one of the artistic advantages of reflexmate over selfmate, namely the presence of more varied mates (on average).
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