Cutting off the king

Cutting off the king means creating a barrier the opposing king cannot cross. A rook commonly does this by controlling an entire rank or file. Because the king may not enter an attacked square, it is kept away from a pawn, a defensive zone, or the attacking king.

The technique is especially important in rook endings. The side with an extra pawn tries to exclude the defending king while its own active king supports the advance. In general, the farther the cut-off king is from the critical area, the harder its defensive task becomes.

A cut-off does not win by itself. The rook must remain safe, the controlled line must stay open, and the defender may compensate with side checks, meaning checks delivered from the flank, or with active rook play. In some positions, a one-file cut is insufficient. In bridge building, however, keeping the defending king away is a central condition.