Duck Chess is an exciting and absorbing new chess variant invented in early 2016 by Dr Tim Paulden, the president of Exeter Chess Club, Devon, England.
The basic principle of the game is very simple: in addition to the usual pieces, the two players have joint control of a small rubber duck which acts as a “blocker” (i.e. nothing can move onto or through it), and which must be moved to a new square after every turn. The goal is to successfully capture the opponent’s king.
Rules of Duck Chess
To play Duck Chess, you need two players, a standard chess set, and one rubber duck (small enough to occupy a single square of the chessboard).
Each player’s turn always consists of two actions: (1) making a standard chess move, and then (2) moving the duck to any empty square on the board. (The duck must be moved – it cannot be left where it is.)
The duck acts as a “blocker” – i.e. you may never move a piece onto or through the square currently occupied by the duck (though knights may jump over it). The duck cannot be captured.
You win the game by capturing the opponent’s king.
There is no concept of check – i.e. it is permissible to make a chess move that does not remove an existing attack on your king, or to make a move / capture with your king that places it on an attacked square. (Of course, if you do this, you are strongly advised to use your duck movement to block the attack, to prevent your opponent from capturing your king – though doing so is not compulsory.)
You may castle in the same way as normal chess, provided that the king and rook involved have not yet moved, and all the squares between them are empty. (All check-related restrictions on castling are lifted, as there is no concept of check.)
There is no stalemate in the usual sense – for instance, the position (WK a1 / BK a3 / Duck b1) with White to move is a win for Black, since White is forced to move his king to either a2 or b2, where it can be captured by Black’s king. (Of course, in this instance, White has no possible way to block with the duck.)
In place of stalemate, Duck Chess has the following special “fowling” rule: if the player on turn has no possible moves whatsoever – not even a king move onto an attacked square – then the player without a move has been “fowled” and wins the game immediately. (Due to the extreme difficulty of arranging such a position, this rule has virtually no impact on practical play – it is mainly relevant to composed Duck Chess problems.)