Tempi and zugzwang

A saved waiting move, usually a pawn move, that transfers the critical obligation to move to the opponent.

A maneuver that returns to an equivalent position with the move transferred to the opponent.

A position in which every legal move makes the situation worse for the player whose turn it is.

A position in which either side would be disadvantaged if it were that side's turn to move.

A pair of king squares where entering first allows a matching reply that creates zugzwang or decisive penetration.

A reciprocal-zugzwang pawn position where the player to move must abandon a pawn and loses.