TeX User Group >> PracTeX Journal >> Issue 2007/1 >> Square Concepts

Solution for: Task F

The answer is: ``You can not advance the pawn to the last rank, but you can win the game!''. If the blocked pawns to the right would not be there, it would indeed be a draw. But having them on the board lets you tackle your contrahent down.

All you have to do is: ``Let go of the advanced pawn.'' Leave it alone, and start off to attack the remaining pawns of White. Since the white king has to capture a4 first, else it promotes, you will arrive ahead of time and win both pieces. This should be your plan for this constellation: ``Keeping White busy by forcing him to capture your advanced pawn and decoying him further away from the center of the board.''

Now let us look at this from a more technical point of view and watch a concrete series of moves. At first we have to get out of the corner, so after the moves 1. ... Ka3 2. Kc3 Black plays 2. ... a4

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Notice how things are turning here. Now Black, instead of White, holds what is called the ``opposition''. He can wait for the move of White and then decide where to go next, which is often an advantage in endings like this one. However, White does not have a lot of choices...he has to play 3. Kc2. On all other moves, like 3. Kc4, Black can win by 3. ... Kb2

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which guards the a-pawn on his last three steps to the promotion.

But after the mandatory 3. Kc2 Black escapes his prison with 3. ... Kb4.

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Again, White has no choice but to further attack your isolated pawn with 4. Kb2. If he tries something fancy like 4. Kd2 you can always strain at his leash by advancing the a-pawn. Keep him busy, he has to come back!

Assuming that White gives in by 4. Kb2 Kc4 5. Ka3 Kd4, the following position is reached:

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The advantage for Black is evident now: White captures the a-pawn but will have to stop two connected pawns on the g- and h-file with his bare hands, so to speak.

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