Originally posted by nimzo5
I think your notion of "common" is at best subjective.

Well let's see some references that use other definitions. Averbakh and Dvoretsky use it in situations where the game result would change, and the latest Oxford Companion to Chess shares this definition.

And tell me how you define zugzwang, including which of my last two examples are zugzwang or not.

Originally posted by Varenka
Well let's see some references that use other definitions. Averbakh and Dvoretsky use it in situations where the game result would change, and the latest Oxford Companion to Chess shares this definition.

And tell me how you define zugzwang, including which of my last two examples are zugzwang or not.

As noted in Winter's piece, the Oxford companion to chess has vacillated on the definition. Almost every source I have looked at recognizes the debate over what precisely zugzwang is and isn't.

Not a big deal really, but the tone of your posts (imo) sounded like you were in possession of the truth. I am simply suggesting it is not so clear.

Originally posted by nimzo5
Varenka- Your argument hangs on the notion that Zugzwang is only legitimate if there is no other way to win.

It appears this is not the historical convention of the word, at least if you can trust Edward Winter on the matter. He sites Heidenfeld in the 1972 BCM as the source of your definition. Since the word has been floating around since the 1850's I am ...[text shortened]... are not in possession of the "truth" but in a camp arguing for a more stringent definition.

The Winter article is a worthy read:

http://www.chesshistory.com/winter/extra/zugzwang.html

Originally posted by Varenka
And people don't dispute it for nothing either...

http://en.wikipedia.org/wiki/Immortal_Zugzwang_Game

Interesting link. I think Soltis and Heidenfeld both miss Nimzovich's point: ...R5f3 is a stronger move if Black waits for White to play g4 or Kh2 first. Either move self-pins Bg2 and only allows White to get a Rook for the Queen rather than two Rooks for a Queen and Bishop.

Note that Soltis does think that such a zugzwang game is possible. He presents the Dvoretsky game in which again White gets outplayed culminating in zugzwang. Black is probably winning anyway, yet takes the opportunity to use zug to efficiently finish the opponent.

Originally posted by Varenka
[b]in a camp arguing for a more stringent definition

I didn’t suggest there is a single correct usage; I suggested there is a more common usage. And in terms of this common usage, I refer to the current state of chess literature and not how I think it should be.

So based on people’s suggestions above for defining zugzwang (Black to play in each c ...[text shortened]... because of the check?! Is this right? Is there some definition that states “but not in check”?[/b]

I can play the same games.

I'm betting you think this is zugzwang after 1.Rc3, since white needs it to force the win.

White to play

Now, let's add to the diagram.

By your definition, 1.Rc3 no longer causes zugzwang, since white could also win with 1.Rxh3 and promoting the pawn, even if Black could "pass". The best winning method, 1.Rc3, still works exactly the same way, i.e. by compelling Black to move, and yet it's no longer zugzwang because of a trivial pair of pawns in some faraway sector of the board.

This is my main objection to your definition of zug.

Originally posted by SwissGambit
Interesting link. I think Soltis and Heidenfeld both miss Nimzovich's point: ...R5f3 is a stronger move if Black waits for White to play g4 or Kh2 first. Either move self-pins Bg2 and only allows White to get a Rook for the Queen rather than two Rooks for a Queen and Bishop.

Note that Soltis does think that such a zugzwang game is possible. He present ...[text shortened]... obably winning anyway, yet takes the opportunity to use zug to efficiently finish the opponent.

R5f3 is a stronger move if Black waits for White to play g4 or Kh2 first

The claim is that White is in zugzwang.

I gave the position to some top engines with White to move. I then gave White the option of skipping a move by changing the position to be Black's move. All of the top engines I tried prefer Black even more if it is Black's move. So why is this a disadvantage for White having the move?

Originally posted by SwissGambit
This is my main objection to your definition of zug.

The rules of chess say that a player is not allowed to pass on any move, but we obviously don't regard every position as zugzwang on this basis alone. To be zugzwang it also has to include some disadvantage that would not be incurred if the move could be skipped.

For your first position, Black can avoid losing if he were allowed to skip on certain moves. So having to always move if a disadvantage as it means losing.

In your 2nd position, Black cannot avoid losing even if he were allowed to skip moves. So what disadvantage is he incurring in this case by having to move? You regard it being a disadvantage to be mated sooner rather than later, fair enough. But outwith the 50 move rule, the rules of chess regard the distance to mate as being the same: 1 point is awarded regardless. You have your view of "disadvantage" and I have mine.

I don't know how to put annotations in the game (if someone could tell me that'd be great) so I put my comments beneath the game (not much to comment on anyway). It's a game I played a long time ago on here and I'd like to know if anyone thinks the end of this game could be considered a Zugzwang.

White actually resigned after 36 ...b5 because he saw that he couldn't play Rxb5 to free his rook because of Nxd4+. So he'd need to move his king, after which his rook is trapped. His king can get to the rook before mine can, but he can never get it free. So after my knight wastes a move, White has nothing better than Rxb5 because his only other choices are a king move (which hangs the rook) or his one pawn move, which gives me a passed pawn and he loses the rook next move anyway.

I'm on the fence as to what is - and is not zug. It would seem to me SwissGambit is most correct, but Varenka also has good points. The following game I think illustrates zug very well. It is a famous game between Spassky and Karpov. I suppose if I had to define zug I would say its a moment in time that a player must move in such a way that it makes his position worse - whether that be by an accelerated checkmate (Mr. Gambit) or a new initiative. By this simplistic view I would also consider Mr. NatScience's game to be zugzwang as well.

(if your not sure where the zug takes place...look at move 35)

Q