Next up (tomorrow) is Tattersall No. 58, but while analyzing it I realized my understanding of 3P vs 3P was defective. So first a digression into Fine (1941)
Basic Chess Endings. I also checked the new edition Fine / Benko (2003), but Benko did not making any changes to this particular example.
Fine no.96
Quote:Reuben Fine wrote:
Starting from the symmetrical position (No. 96) the person who does not move always retains an extra tempo, by simply copying his opponent's moves. (my emphasis)
The highlighted part is what I remembered, and it was messing me up, because for the case of 3 vs 3 it is
not true. There is no general rule of whether black should copy or not copy white's moves, and this is what I was finding as I analyzed Tattersall.
In order to get a legal pgn, I created a zugzwang position with kings, and copied Fine's analysis to it. I also flipped a-h from Fine's diagram to make it easier to compare with Tattersall No.58, when we get to that.
Quote:Reuben Fine wrote:
1. c3 c6 2. b3 b6 3. a3 a6 4. c4 a5!
(4...c5? 5. b4! a5 6. bxa5 bxa5 7. a4)
5. b4
(5. a4 c5)
(5. c5 bxc5 6. a4 c4! 7. bxc4 c5)
5...a4 6. b5 c5
or 6. c5 b5
Note that on the fourth move, Fine has black answer 4.c4 with 4...a5! (his exclam), in parentheses showing the "copying" move as losing. This is clearly a case of "do as the GM does, not as the GM says".
Quote:Reuben Fine wrote:
From this last (sic) variation we can draw the all-important conclusion that an exchange loses the tempo. (his emphasis)
As far as I can tell, this second statement is correct, as long as it is a simple exchange of PxP followed immediately by ...PxP. Fine's variation
1. c3 c6 2. b3 b6 3. a3 a6 4. c4 a5 5. c5 bxc5 6. a4 c4 7. bxc4 c5 shows that an "exchange" of pawns by sacrifice and counter-sacrifice does not change the tempo.
Putting Fine's analysis in the computer was an eye-opener. I thought that black had more choices early, and that it was only later that the moves mattered. The computer showed just how critical each choice is. Even Fritz 6 on my consumer grade laptop is able to calculate to the end, or at least after a couple of pawns have been committed. The real shocker is that Fine's
1.c3 c6 2.b3 b6 actually loses for black! So much for copying. There follows
3.c4 c5 4.a3 a6 reaching Fine's parenthetical note 4...c5?
2...c5 is the only move there. Another point, which I already knew from analyzing Tattersall, is that in Fine's variation
1. c3 c6 2. b3 b6 3. a3 a6 4. c4 c5? 5. b4! black can exchange
5...cxb4 6.axb5. Now black has a potential outside passed pawn, and for this reason I
generally would prefer to start with 1.a3 instead of 1.c3. But in this exact position it doesn't matter,
6...a5 7.c5! bxc5 8.bxa5! and the tablebase confirms a win for white, although queen endings are not my favorite.