Thursday, November 15, 2007

Got Zugzwang?

I reached this position with Black after 44. ... h5:

My opponent and I had already been mumbling about a draw, but I insisted we play on for a couple more moves. Turns out that Black is winning, thanks to zugzwang! Once the pawns on the kingside are stuck, the White king will have to relinquish the protection of the c5-pawn. Black can then take the pawn and proceed into a winning endgame.

Lesson learned: if a situation looks hopelessly stuck and drawish, check again, and see if the position's got zugzwang.

Here are two illustrative positions from Bruce Pandolfini's Weapons of Chess:

In the first example, White is winning regardless of whose move it is; in the second example, whoever moves first wins.


jrobi said...

I enjoyed going over this one. Good post Christian!

Anonymous said...

Cursed passwords with numbers i always forget them.... anyway a helpful little tidbit supposing the kingside pawns where out of the equation if you ever find yourself in this situation where it is your turn to move and you will lose the pawn a forced draw is to move one square back and or out of opposition with Kb4 that way after Kxc5 no bridge building will be able to be made and will result in a draw after opposed to the move Kc3 which loses on the spot after 1..Kxc5 2Kc2 Kc4 3.Kd2 Kb3 4.Kc1 Kc3 5.Kd1 c5 6. Kc1 c4 7. Kb1 Kd3 queening in 3 the same situation happens if he moves Kb3 or Kd3. In short in situations with a pawn blockading a pawn and it is your move playing the king out of opposition will always draw with best play if the opponents king moves you into oppostion on the pawn file you will lose. A bit long winded but useful none the less. -UnorthodoxPlayer-

Christian said...

Not always. If your pawn has already advanced to the fifth or sixth rank (and isn't a rook or knight pawn), it's a win even if the enemy king does have the opposition, no?

Anonymous said...

Ugh perhaps i made my statement too open to loopholes so here is the loophole free revised version. But firstly since any positon where it would be blacks turn to move with an enemy pawn on sixth rank and mine on the seventh it would either be an illegal position or a position that couldnt be reached from my example if you meant anything else "If the opponents king moves you into opposition on the pawn file you will lose" should be able to take care of it. So to answer your question yes it will always be a draw as long as the black king has the opposition and there is 1 rank between blacks king and whites pawn. And to avoid any loopholes in the future if the white king and pawn is adjacent to the king and plays pawn check you move to the pawn file either back one or directly over it doesnt really matter i suppose, until the king gets adjacent with the pawn again and you seize the opposition to once again have the opposition with a rank between the pawn and enemy king. Darn seems i yet again made another long winded post. -UnorthodoxPlayer-