Protected passed pawn

A protected passed pawn is first a passed pawn: no enemy pawn stands between it and the last rank on its own vertical file or either neighboring file. On reaching that rank it can become another piece. A second friendly pawn also protects it diagonally. That supporting pawn does not have to be passed itself.

The protection is particularly important against a king. While the supporting pawn remains in place, the opposing king normally cannot capture the passer because it would step onto a square attacked by that pawn. The defender may instead have to place a piece directly in front of the passer, a method called a blockade, or attack the supporting pawn first.

A protected passer is durable, not unstoppable. A piece can immobilize it, the supporting pawn can be removed, or the passer can be attacked from behind. Its actual strength depends on the distance to the last rank, support from the king and pieces, and whether the opponent has time to establish a blockade.