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
Madrasi chess on g2). In addition to Madrasi RI, another variant is Isardam ("Madrasi" spelled backwards), in which only moves that do not lead to a Madrasi paralysis are legal. Madrasi chess Madrasi chess is a chess variant invented in 1979 by Abdul Jabbar Karwatkar. The game uses the conventional rules of chess with the addition that when a piece is attacked by a piece of the same type but opposite colour (for example, a black queen attacking a white queen) it is paralysed and becomes unable to move, capture or give check. Most of the time, two like pieces attack each