Why the rook's pawn is different
With a centre pawn the attacking king can go round the defending king on either side. With a rook's pawn there is only one side, and once the defending king reaches the corner in front of the pawn, there is no way to drive it out. Every attempt ends in stalemate or the loss of the pawn.
To win, the attacker needs his king on g7 or g8, the key squares on the neighbouring file. The defender's job is to stop that.
The defender's method
Head for the corner at once, or for f8 and f7. From those squares your king keeps the white king off g7 and g8, or shuts it in on the h-file in front of its own pawn.
In this position only Ke7 draws. Every other move, even Kd7, is too slow and loses. After Ke7 Kg6, Kf8 is again the only move, and if the white king walks in front of its pawn to h7, Kf7 locks it in.
Stalemate is your friend
When the pawn reaches h7 with check, go into the corner with Kh8. White then has nothing better than stalemate, because any other king move leaves the pawn undefended. Stepping out with Kf8 instead loses, because the pawn promotes.
Remember
- Run for the corner
- f8 and f7 lock the king in
- Never let the king reach g7
- Stalemate saves the defender