Rook and Bishop vs Rook: The Philidor Position

Watch the method: press play to see the winning idea run, or step through it move by move.

Rook and bishop against a lone rook is a theoretical draw, yet the defence is so demanding that strong players lose it regularly. The stronger side aims for Philidor's position, known since 1749.

The setup. The defending king is pressed to the edge with its rook stuck in front of it. That is the danger zone: with the king on the edge and the rook passive, the attacker has a forced sequence.

Only one move starts it. 1.Rf8+ is the sole winning move here. It forces the black rook onto e8, and 2.Rf7 then takes the seventh rank. Rh7 and Rb7 drive the rook away from its king, and the mate follows.

Corner colour decides. The king is herded toward the corner that matches the attacking bishop's colour, where the bishop covers the escape squares.

The knight file is the exception. The mate exists on the central, bishop, and rook files, but on the knight's file the same setup is only a draw, so as the defender aim for the knight-file corner and as the attacker aim for the bishop's colour. And the defender's rook belongs on its own second rank, where its check comes on the colour opposite the bishop and cannot be blocked. Zugzwang that rook off the second rank, then win it with the bishop.

In this drill the defence never cracks. Find Rf8+ and execute the maneuver.