Rook Endgame
The Philidor Position
Also known as: Third-Rank Defense
The Philidor position is the fundamental drawing method in rook-and-pawn versus rook endgames, the essential defensive counterpart to the winning Lucena position. It applies when the defending king stands in front of the enemy pawn, and it saves the game by a technique known as the third-rank defence. The defender keeps the rook on its own third rank, denying the attacking king the sixth rank it needs to make progress. The moment the pawn advances, the rook swings to the far edge and checks the exposed king from behind, and the checks never stop. Knowing both Philidor, the draw, and Lucena, the win, is required equipment for any rook endgame.
1. … e3 2. Ra8 Kf3 3. Rf8+ Ke4 4. Re8+ Kf4 5. Rf8+ Ke5 6. Re8+
The fundamental drawing position
The Philidor position is the basic draw in rook-and-pawn versus rook. It is available to the defender whose king has reached the square in front of the enemy pawn. The saving idea is the third-rank defence: the defending rook is placed on its own third rank, where it prevents the attacking king from occupying the sixth rank and gaining the space it needs to win.
In the diagram White is the defender, with the king on e1 and the rook on a3, while Black attacks with the king on f4, the pawn on e4, and the rook on h4. As long as the pawn stays back, the rook on the third rank holds everything together, and Black cannot force a breakthrough.
The demonstration
Black tries to make progress by advancing the pawn: 1...e3. But this is exactly the moment the defence changes gear. With the pawn on the third rank it no longer shelters the black king, so White abandons the third-rank guard and switches to the rear with 2.Ra8.
From behind, the rook checks endlessly. After 2...Kf3 3.Rf8+ Ke4 4.Re8+ Kf4 5.Rf8+ Ke5 6.Re8+, the black king can find no shelter from the checks. Because the advanced pawn can no longer protect its own king, Black can make no headway, and the game is a draw.
Why the defence holds, and when it fails
The logic is a neat division of labor. While the pawn is still back, the defending rook sits on the third rank and keeps the enemy king off the sixth; once the pawn moves up to the third rank, the same rook drops to the far end of the board and harries the king from behind. In each phase the pawn's own advance is turned against it, since it cannot both advance and shield its king.
The defence has one requirement: the defending king must stand in front of the pawn and not be cut off from it. If the attacker manages to cut the king off from the pawn, the Philidor draw is unavailable and the attacker may reach the winning Lucena position instead. For that reason Philidor and Lucena are always studied together.
Key ideas
- The Philidor position is the fundamental draw in rook-and-pawn versus rook.
- It is for the defender whose king stands in front of the enemy pawn.
- The third-rank defence keeps the defending rook on its third rank to deny the enemy king the sixth.
- When the pawn advances, the rook drops behind and checks from the rear without end.
- The advanced pawn can no longer shelter its king, so the checks are perpetual and the game is drawn.
- If the defending king is cut off from the pawn, the defence fails and the attacker may reach Lucena.
Typical plans
White
- Keep the rook on the third rank to bar the enemy king from the sixth.
- The moment the pawn advances, swing the rook to the far edge and check from behind.
- Continue the rear checks indefinitely, since the pawn can no longer shelter its king.
Black
- Advance the pawn and try to escort the king forward to the sixth rank.
- Look for shelter from the checks behind the pawn once it has advanced.
- Aim to cut the defending king off from the pawn, which would fail the Philidor defence and allow Lucena.