Rook and bishop versus rook endgame

It is generally a theoretical draw, but the rook and bishop have good winning chances in practice because the defense is difficult.

[3] Tony Kosten has seen the endgame many times in master games, with the stronger side almost always winning.

"[5] David Howell observed, "Especially below elite grandmaster level, this is one of the hardest endgames to draw.

Edmar Mednis estimated that less than 4% of starting positions that occur in games are theoretical wins.

[7] In 1749 François-André Danican Philidor (1726–1795) published a position in which the superior side can force a win.

Other winning and drawing positions were studied by Adolf Zytogorski,[8] Tassilo von Heydebrand und der Lasa, Josef Kling and Kuiper, and André Chéron.

[9] Many of the longest chess games on record involve this endgame since at one time the fifty-move rule under which a draw could be claimed after fifty moves with no capture was extended to one-hundred moves for this combination of material.

Anatoly Karpov played a rook versus rook and bishop ending in a 2003 game with 15-year-old Teimour Radjabov, which went 113 moves before an indignant Karpov claimed a draw by invoking the 50-move rule with only 14 seconds remaining on the game clock.

Alternatives are: This idle move is necessary because the black rook must remain on the e-file, so it is forced to its next best position on e1.

Now White completes the following maneuvers, getting the bishop back to d5 with gain of tempo.

It does not work if the kings are on the rank or file next to the edge – those positions are a theoretical draw, but difficult to defend.

If the kings are on a rank or file on the edge of the board the position is a win, but by a different method.

Switching the attacking rook to the other side of the king is no longer dangerous.

In this position, if the pieces on the e-file were moved to the f-file, then if 1.Ke5, the response 1...Kg8 puts the black king dangerously close to the corner.

[27] In this position from a 1991 game between Alexandar Budnikov and Maxim Novik, White would like to get his king to d6 and bishop to d5, to win by a method of Philidor (see Philidor position); however, the pin of the bishop to the king prevents it.

[28] There are some key ideas for the defender to observe: The game continued: and the position is back to the basic Cochrane position, rotated 90 degrees, and the fifty-move rule is closer to coming into effect.

The Budnikov versus Novik game continued, with the Cochrane position being reached again.

[33] This 1997 game between Joose Norri and Suat Atalık illustrates the second-rank defense.

Attempting to get the rook behind the black king would get to a lost Philidor position: 87.Rc8?

[35] The second-rank defense was used by 16-year-old Magnus Carlsen in this 2007 game against Loek van Wely.

Compared to the Philidor position, the kings are not opposite each other and the defending rook can prevent checkmate.