Breaking down a passive fortification can be difficult, even when you have a large positional advantage. If you have seen my article “A Fatal Compulsion”, you know that one of the methods is to use Zugzwang – your opponent’s compulsion to make a move. This is the equivalent to a siege – your opponent would be safe if he could sit in his castle and not move, but eventually he runs out of supplies and has to do something.
The subject of this article is a long and fantastic endgame played by Aron Nimzowitsch in the Winterthur 1931 tournament. It goes through several phases, with changes in between each. The endgame - which begins with a knight against a bishop - encompasses nearly thirty moves. First there are maneuvers in the minor piece ending, then a king and pawn ending, a queen ending, and yet another king and pawn ending. Finally Black wins the majestic endgame by only one tempo.
The adventures start with this position:
Clearly Black has a huge positional advantage. It is the standard “good knight versus bad bishop”, and additionally he has some more space. Most of the white pawns are on the dark squares, blocking his own bishop; meanwhile, this situation means that White is very weak on the light squares.
Black’s advantage is undisputed – however, this doesn’t mean he can win. To actually win the game, he will have to break through, to win something or create a passed pawn. In the above position, there is no way for Black to break in with his king besides the e4 square, which can be guarded by the white king. The bishop is able to guard White’s two main weaknesses – the g3 and c3 pawns. The only way to win will be through the use of Zugzwang – compelling White to make a move which destroys his own position.
We will now look at how Nimzowitsch won this ending, in stages:
Black has completed the first triangulation, forcing the white king back. But now what?
Black sent the knight on a long journey, from its comfortable home on e4 all the way to b1 - where it is now trapped. But he forced the white bishop to defend the c3 pawn from a1 - and it too is trapped. Still White is managing to hold Black off.
By a second triangulation, Nimzowitsch forced his opponent to go capture the knight, and in doing let the black king in. But White was not ready to resign yet, and played a resource that Nimzowitsch had to take into account long before.
The counter-sacrifice led to a king and pawn endgame where there was a race of passed pawns. Both queened at the same time. But now Nimzowitsch forces the queen trade, leading to a second king and pawn ending and a second race, which Nimzowitsch had seen long ago he would win by one tempo.
Finally after many transformations - but all logical and forced - Black wins by a single tempo. As far as I can see, there was no other way to win (besides 63...Kxf4, which at that point would win as well, but with more difficulty), nor any way to strengthen the defense. Attack and Defense were balanced, and Black's positional advantage was carried through decisively.