Rookending continued

In the previous post we got a rookending and we defined the goals both sides should try to reach. Continuing the pursuit of the goals was rather straightforward and white had to give up his rook to prevent promotion of the kingside passer. But then I encountered the following position:

diagram 1

Black to move.
Here you have to be very carefull, the minutest slip means a draw here.
First we have to redefine the goals of both sides.

The goal for white is pretty obvious:
The pawn must promote and the white king must keep the road to promotion clear.
White needs at least 7 moves for that.

Black must conquer the pawn. The most logical place is to intercept the pawn is at g8, which is allready under attack by the rook. This means that the rook is already standing well, this means that the black king must head for h7 or f7. h7 can be reached in 8 moves while f7 can be reached in 5 moves.

The following moves the main goals continue to be the same for both sides, but tactically every position needs a redefinition of the method to go further. White can make the road of black towards blacks goals longer, but he needs to invest tempi himself in order to do so. As long as the extra tempi on both sides don't tip the balance, black continues to be fine. In diagram 1 both 1. ... Kd3 and 1. ... Kc3 (surprisingly!) brings black closer to his goal.

diagram 2

 White to move. White can invest a tempo to make the road of the black king towards f7 a few tempi longer: 2.Ke5

diagram 3

 Black to move. The black king needs now 6 tempi to reach f7 and 6 tempi to reach h7. But he can invest a tempo himself to force white to shorten the way for blacks king with 2. ... Rg8

diagram 4

 White to move. White has no choice than to protect his pawn, thus shortening the way for the black king towards f7. With 3.Kf5 the white king covers the most squares in front of the pawn, the road to promotion.

diagram 5

 Black to move. The rooks stands well for the moment. 3. ... Kd4 brings the black king one step closer. Surprisingly Kc4 works equally well!

diagram 6

 White to move. 4.g5 is the only move that makes sense.

diagram 7

 Black to move. 4. ... Kd5 brings the black king one step closer.

diagram 8

 White to move. 5.Kf6 makes the road of the black king longer while it covers more squares on the road to promotion.

diagram 9

 Black to move. 5. ... Kd6 prepares to squeeze the white king from the f-line by covering the e-file. This move is only understandable in combination with Rf8+.

diagram 10

 White to move. 6.g6 is the only move that makes sense.

 Black to move. 6. ... Rf8+ squeezes the white king from the f-line so that the black king can approach the white pawn.

White to move. It's over. 7.Kg7 allows to squeeze the white king further by Ke7 while after 7.Kg5 the black king simply approaches the pawn. Both moves increase the amount of tempi white needs to reach his goal while the amount of black's tempi diminishes.

You see that play becomes critical when both sides need about the same amount of tempi to reach their goals. When that amount is far off balance, play is simple and straightforward.