Philidor position

The Philidor position (or Philidor's position) usually refers to an important chess endgame which illustrates a drawing technique when the defender has a king and rook versus a king, rook, and a pawn. It is also known as the third rank defense, because of the importance of the rook on the third rank cutting off the opposing king. It was analyzed by François-André Danican Philidor in 1777. (Also see rook and pawn versus rook endgame.) Many rook and pawn versus rook endgames reach either the Philidor Position or the Lucena Position. If played accurately the defending side tries to reach the Philidor Position; the other side tries to reach the winning Lucena Position. Jesús de la Villa said "[The Philidor position] is perhaps the most important position in endgame theory" (de la Villa 2008:125).

Philidor analyzed many positions, some of which have his name associated with them (see the subsequent sections).

The diagram shows an example of Philidor's position. The important characteristics of the position are (from the point of view of the defender):

Black would like to get his king to the e3-square and threaten checkmate to force the white king away from the queening square of the pawn, e1. The white rook on the third rank prevents that. If Black checks with the rook from the side, White simply keeps the king in front of the pawn by alternating between squares e1 and e2. If Black offers an exchange of rooks White should take it, since the resulting king and pawn endgame is drawn (see King and pawn versus king endgame).

So Black's only winning chance is to advance the pawn. The basic idea is for the defender to keep his rook on his third rank until the pawn advances to that rank, then check the opposing king from behind. Here is a possible continuation:

If 1...e3, advancing the pawn immediately, then 2. Ra8 draws since Black's King cannot escape checks without losing his e-pawn, when the resulting position with each side playing with a King and a Rook, is a draw.

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