[QUOTE=Frylock]
But if it turns out that a complete analysis of chess shows that black can force a win, then wouldn’t every first move from white count, strictly speaking, as weakening his position?
[/quote]
That’s true.
However all the evidence points to White having a clear advantage, and I would guess the likeliest result of solving chess would be 90% draw / 9.9% White wins / 0.1% Black wins.
[QUOTE=Frylock]
Maybe we should make the notion of “weakening one’s position” more precise. What do you mean by that phrase in your definition of zugzwang?
(I always thought of zugzwang as being the following situation: If it were possible to pass, that would be your best move. On that understanding, white certainly would be in zugzwang if black can actually force a win from the opening position.)
-FrL-
[/QUOTE]
Being in zugswang means any move weakens your position fatally, so another way to say it is that your best move is to pass (which of course is not legal in chess!).
I gave one example already:
White King d6, White pawn e6, Black King d8. White to move draws, Black to move loses.
(1. e7+ Ke8 2. Ke6 stalemate; 1. … Ke8 2. e7 Kf7 3. Kd7 and promotes.)
Here’s another:
White King e4, White pawns c4,g4, Black King e6, Black pawns c5,g5. White to move draws, Black to move loses.
(1. Kd3* Ke5 2. Ke3 draw; 1. … Kd6 2. Kf5 wins.)
*not 1. Ke3? Ke5 winning.
You can generate such positions with more material, but it is rare, so it just wouldn’t apply to the starting position.