Undermining (chess) Undermining (chess) Undermining (also known as removal of the guard, or removing the defender) is a chess tactic in which a defensive piece is captured, leaving one of the opponent's pieces undefended or under-defended. The opponent has the unpalatable choice of recapturing or saving the undefended piece. A possible response is to sacrifice the piece whose defense was undermined before capturing the piece which just took the defender. Kramnik–Topalov in the seventh round of the 2004 Linares chess tournament reached the diagrammed position with White to play. The black knight on a4 is defended only by the black pawn on
Fairy chess piece David Parlett used a notation to describe fairy piece movements. The move is specified in the form m={"expression"}, where "m" stands for "move", and the "expression" is composed from the following elements: The following can be added to Parlett's to make it more complete: The format (not including grouping) is: <conditions> <move type> <distance> <direction> <other> On this basis, the traditional chess moves (excluding castling and "en passant" capture) are: Ralph Betza created a classification scheme for fairy chess pieces (including standard chess pieces) in terms of the moves of basic pieces with modifiers. Capital letters stand for basic leap