Frontal defense

The frontal defense occurs in king and rook against king, rook, and pawn. The defending rook stands in front of the pawn, along its direction of travel, and gives frontal checks to the attacking king.

The aim is to stop the king from reaching a safe square from which it can support promotion. Each check makes the king retreat, move aside, or try to approach the rook. The defending rook may also offer an exchange when the resulting king and pawn versus king ending is drawn.

Space is crucial. A rank is a horizontal row of the board. As a guide, the defense has good chances when at least three ranks separate the pawn and the defending rook. This separation preserves checking distance. The farther back the pawn is, the more time the rook has to repeat the procedure.

The rule of three does not guarantee a draw. The pawn's file, the side to move, the defending king, and possible shelters for the attacking king can change the result. Central and bishop pawns often create more difficulty than a rook pawn, so the exact geometry must still be checked.