In parts I and II we studied the kings battle in a single pawn endgame when the pawn isn't a wing pawn. Let's now study some more important technicues and theoretical positions in simple pawn endings.
We already saw in part I that it's impossible to win with a wing pawn if the defending king manages to get in front of the pawn. The attacking king in front of the pawn can also cause problems.
White wins with the h6-pawn if his king manages to get into one of the two key squares depicted in the next diagram (provided black can't capture the pawn next turn).
Black can draw for example by placing his king into f8 (unless white has his king in g6 when he would win with h7). Even if the pawn is further back the battle is mainly about the same squares although for the attacking player it may be impossible to head directly towards the key squares (g7,g8) because this would lead to the capture of the pawn.
Although our topic are the pure pawn endings it should be mentioned that the following position is also drawn.
If black just keeps moving his king between the squares g8, h8, h7 best white can do is to stalemate the black king. Black only draws because white has a wrong bishop. The position would be easily won if white had a dark-squared bishop instead because then it's easy to force the black king away from the corner. Any other piece than a bishop would also quarantee white's victory.
The rule of the square
Very usefull tool for evaluating positions where the defending king is forced to chase a fleeing passed pawn is the rule of the square. Consider the position in the following diagram. If it's black to move, he can draw with 1... Kf4 stepping into the square of the pawn. If it's white to move, he wins with 1. b5 because the square of a pawn on the 5th rank is smaller than a one on the 4th rank and therefore black is now too late.
When dealing with a pawn on starting square one must remember that it can move two squares. Therefore the square of a pawn on the 2nd rank is the same as for a pawn on the 3rd rank.
Creating a passed pawn with a breakthrough
When both sides have several pawns it may be necessary to created a passed pawn before trying to promote it. Sometimes this may require sacrifices. Below is the standard example on this theme.
If it's black to move he can step into the square of the c-pawn and the presented plan doesn't work for white anymore. Actually black even wins in this case because his king is closer to the action.