Szén position

The Szén position is a defensive formation in the pawnless ending of rook against rook and bishop. It is named after Hungarian master József Szén, who identified this drawing resource.

Its main visual feature is that the kings form an L, with a separation resembling a knight's move. The weaker side's rook defends from the side of its king that offers more room. From there it can prevent the opposing rook and bishop from completing a mating net, a formation that controls the escape squares and can force checkmate.

The idea does not depend on fixed coordinates. The position may be mirrored or rotated. What matters is preserving maneuvering room for the defending king and keeping the rook on the correct side. If the king is driven too close to the corner or the rook changes sides without a reason, the formation may lose its stability.

The second-rank defense belongs to the same ending, but it arranges king and rook on a line one square from the edge. The Szén position is recognized by the kings' geometry and the choice of the roomier side.