[edit] Philidor's position, rook and pawn versus rook

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

• the defending king (White in this diagram) is on the queening square of the pawn (or adjacent to it). The pawn can be on any file.
• the opposing pawn has not yet reached the defender's third rank (its sixth rank).
• the opposing king is beyond the defender's third rank.
• the defender's rook is on the third rank, keeping the opposing king off that rank.

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 chance of progress 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:

1. ... Rb2

2. Rc3 Ra2

3. Rb3 e3

Black plans to move Kf3, then if he is unopposed, checkmate with the rook or advance the pawn. (A passive defense does not work.)

4. Rb8!

Since now Black's king can not move to e3, it is safe to move the rook away to the far end of the board (the defender's seventh or eighth rank). Note that 4.Rb4+ (??) loses immediately to 4...Kf3 when black will checkmate or force the exchange of rooks followed by Kf2 and promotion of the pawn.

4. ... Kf3

5. Rf8+ Ke4

6. Re8+

The black king can not hide from the checks without giving up the pawn; nor can he approach the rook:

6. ... Kf4

7. Rf8+ Ke5

8. Re8+

The defender's rook must be on his seventh or eighth rank for this defense to work.

To sum up the defense: the defender should keep his king in front of the opposing pawn and keep his rook on the third rank until the pawn advances to that rank, then go to the far end of the board (the seventh or eighth rank) and check the king from behind. If the attacker tries to get his king to his sixth rank by moving his rook to that rank first to block the checks, the defender simply exchanges rooks and has a drawn king and pawn versus king endgame.

Lucena position