Author: Uri Blass
Date: 06:19:48 01/06/06
Go up one level in this thread
On January 06, 2006 at 08:06:13, Joachim Rang wrote:
>On January 05, 2006 at 22:47:06, Dagh Nielsen wrote:
>
>>On January 05, 2006 at 21:14:04, Dann Corbit wrote:
>>
>>>[Event "Moscow RUS"]
>>>[Site "Moscow RUS"]
>>>[Date "1951.??.??"]
>>>[Round "?"]
>>>[White "Gusev, Nikolai"]
>>>[Black "Averbakh, Yuri L"]
>>>[Result "1-0"]
>>>[ECO "B70"]
>>>
>>>1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.Be2 Bg7 7.Nb3 Nc6 8.O-O
>>>Be6 9.f4 Rc8 10.f5 Bd7 11.g4 Ne5 12.g5 Ng8 13.Nd5 f6 14.Be3 b6 15.Nd4 Kf7
>>>16.c3 Qe8 17.Ne6 Bxe6 18.fxe6+ Kf8 19.Nxf6 Nxf6 20.gxf6 Bxf6 21.Bh6+ Kg8
>>>22.Rxf6 exf6 23.Qxd6 Rc6 24.Qxe5
>>>{
>>>4q1kr/p6p/1prQPppB/4n3/4P3/2P5/PP2B2P/R5K1 w - - bm Qxe5; id "Gusev - Averbakh,
>>>Moscow 1951";
>>>}
>>>.. fxe5 25.Rf1 Rc8 26.Bd1 Rc4 27.Bb3 b5 28.
>>>Bxc4 bxc4 29.b3 a5 30.bxc4 Qe7 31.Kg2 Qa3 32.Rf2 Qe7 33.Rf1 g5 34.Rf5 g4
>>>35.c5 Qd8 36.c6 Qe7 37.c7 1-0
>>
>>
>>I have not cranked up my engine, but I think the sacrifice is correct.
>>
>>Reasoning is roughly this, after 25.Rf1:
>>
>>1 White puts bishop on d5
>>
>>2 Now black must block pawn on e6 with piece on e7, or e6-e7+ is curtains.
>>
>>2.1 Black puts queen on e7. Now if black rook is NOT on 8th rank, white wins by
>>Rf8+ Qxf8 e7+. IF black rook is on 8th, white wins by Rf7, for example:
>>
>>2.1.1 Black rook on e8. Rf7, "no black queen move", Rxe7, Rxe7 and white wins by
>>3-2 pawn majority on queenside, black rook on e7 can't move. If Black queens
>>moves away from 7th rank after Rf7, white wins by Rg7+, Kf8, e7+, "black
>>captures pawn e7", Rg8#
>>
>>2.1.2 Black rook on d8. Rf7, "black queen moves away from 7th rank", e7 is
>>curtains.
>>
>>2.1.3 Black rook on a8, b8 or c8. Rf7 Qd8 (Qe8 Rg7+ Kf8 e7+ Qxe7 Rg8#) e7 is
>>curtains.
>>
>>2.2 Black puts rook on e7 (after Bd5). Now Black queen must stay on 8th rank,
>>and black rook on e7. White creates passed pawn on queen side, push it to 7th
>>rank. Black must now put queen on e8, or Rf7-Rxe7 wins. So, Qe8 and now Rf8+
>>Qxf8 Bxf8 Rx"white pawn on 7th" (only move) e7+ and e8Q wins.
>>
>>I don't think there is any non-losing way for black to prevent white from
>>putting his bishop on d5, and I don't think there is any perpetual somewhere
>>above, so, I think the sacrifice is correct.
>>
>>Kind regards,
>>Dagh Nielsen
>
>
>Wow what a good explanation. What is your fee for chess lessons? ;-)
>
>It is not hard to verify the solution with engines with forward analysis but so
>far impossible for engines to solve this from the position in question. Too deep
>lines and in the end zugzwang motives kill every search of today.
>
>Joachim
In order to verify a solution with engines you need to find win against every
defence of the computer to be sure that there is no save for black that you
missed
Here is fruit's analysis at depth 19 after 1.Qxe5 fxe5 2.Rf1(I used history
threshold=50) and later at depth 20
,a - Fruit 2.2, 38'/40+38'/40+38'/40
4q1kr/p6p/1pr1P1pB/4p3/4P3/2P5/PP2B2P/5RK1 b - - 0 1
Analysis by Fruit 2.2:
depth 19:
1. -+ (-1.50): 2...a6 3.Bd1 Rc7 4.e7 Rxe7 5.Ba4 b5 6.Bb3+ Rf7 7.Kg2 Qd7 8.Rxf7
Qxf7 9.Bd5 a5 10.Kg3 a4 11.Be3 h6 12.Bxf7+ Kxf7 13.Kg4
2. ³ (-0.68): 2...Rc8 3.Bd1 Qxe6 4.Bb3 Qxb3 5.axb3 Rb8 6.Kg2 a5 7.Rf6 b5 8.Ra6
Kf7 9.Ra7+ Ke6 10.Ra6+ Kd7 11.Rxa5 Rb7 12.Ra1 Rc8 13.Be3
3. ³ (-0.60): 2...Rc7 3.Bb5 Qe7 4.Ba4 b5 5.Bb3 Rc4 6.Kg2 a6 7.Kg3 Rc8 8.Rf7 Re8
9.Rxe7 Rxe7 10.Bg5 Kf8 11.Bf6 Rg8 12.Bxe5
4. ³ (-0.60): 2...Rc5 3.Bd1 b5 4.Bb3 Rc4 5.Kh1 a6 6.Kg2 Qe7 7.Kg3 Rc8 8.Rf7 Re8
9.Rxe7 Rxe7 10.Bg5 Kf8 11.Bf6 Rg8 12.Bxe5
5. ³ (-0.49): 2...Qe7 3.Bd1 b5 4.Bb3 Rc4 5.Kg2 a6 6.Kg3 Rc8 7.Rf7 Re8 8.Rxe7
Rxe7 9.Bg5 Kf8 10.Bf6 Rg8 11.Kg4 h6 12.Bxe5
6. = (0.00): 2...Qd8 3.Rf7 Rc7 4.Bc4 Rxc4 5.Rg7+ Kf8 6.Rxh7+ Kg8 7.Rg7+ Kf8
8.Rh7+
(, 06.01.2006)
,a - Fruit 2.2, 38'/40+38'/40+38'/40
4q1kr/p6p/1pr1P1pB/4p3/4P3/2P5/PP2B2P/5RK1 b - - 0 1
depth 20:
Analysis by Fruit 2.2:
1. ³ (-0.65): 2...Rc8 3.Bd1 Qxe6 4.Bb3 Qxb3 5.axb3 Rb8 6.Kg2 Re8 7.b4 Rc8 8.h4
Ra8 9.Bg5 h5 10.Bf6 Rh7 11.Rd1 Re8 12.Rd5 Rf7 13.Bxe5
2. ³ (-0.49): 2...Rc7 3.Bb5 Qe7 4.Ba4 b5 5.Bb3 Rc4 6.Kg2 a6 7.Kg3 Rc8 8.Rf7 Re8
9.Rxe7 Rxe7 10.Bg5 Kf8 11.Bf6 Rg8 12.Kg4 h6 13.Bxe5
3. ³ (-0.49): 2...Rc5 3.Bd1 b5 4.Bb3 Rc4 5.Kh1 a6 6.Kg2 Qe7 7.Kg3 Rc8 8.Rf7 Re8
9.Rxe7 Rxe7 10.Bg5 Kf8 11.Bf6 Rg8 12.Kg4 h6 13.Bxe5
4. ³ (-0.34): 2...Qe7 3.Bd1 b5 4.Bb3 Rc4 5.Kg2 a6 6.Kg3 Rc8 7.Rf7 Re8 8.Rxe7
Rxe7 9.Bg5 Kf8 10.Bf6 Rg8 11.Bxe5 Ke8 12.Bd6 Rf8 13.Bxe7 Kxe7
5. = (0.00): 2...a6 3.Bxa6 Qe7 4.Bb5 Rc8 5.Ba4 Qh4 6.e7 Qxh6 7.e8Q+ Rxe8 8.Bb3+
Kg7 9.Rf7+ Kg8 10.Rf6+ Kg7 11.Rf7+
6. = (0.00): 2...Qd8 3.Rf7 Rc7 4.Bc4 Rxc4 5.Rg7+ Kf8 6.Rxh7+ Kg8 7.Rg7+ Kf8
8.Rh7+
(, 06.01.2006)
As you con see even in the second move there are at least 6 moves that you need
to analyze with computers in order to prove that 1.Qxe5 is winning by retrograde
analysis.
Uri
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