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Subject: Re: ECM 1621

Author: Eelco de Groot

Date: 19:02:05 09/24/01

Go up one level in this thread


On September 24, 2001 at 17:30:02, Michel Langeveld wrote:

>On September 24, 2001 at 13:47:44, Peter Berger wrote:
>
>>On September 24, 2001 at 13:32:52, Michel Langeveld wrote:
>>
>>>ECM 1621
>>>
>>> r2q3r/2pkb1p1/p2p1n2/4p1p1/Pp2P1P1/1QP5/1P1P2PP/RNB2RK1 b - - 0 1
>>>
>>>Is 1 .. Rxh2 really winning.
>>>
>>>I see a +2.38 after 1 .. Rxh2 2 Kxh2 ( 2 ... Qh8+ 3. Kg1 Nxg4 4 Rf7 Qh2 5 Kf1
>>>Rh8 6 cxb4 Qh1+ 7 Ke2 Qxg2+ 8 Kd3 Rh3+ 9 Kc2)
>>>
>>>but wat after:
>>>
>>>1 .. Rxh2 2 Rxf6!
>>>
>>>for example:
>>>
>>>2 ... gxf6 3 Kxh2 Qh8+ 4 Kg1 Qh4 (-0.91)
>>>
>>>Michel
>>
>>Why take back here ? How about 2...Qh8 ?
>>
>>A sample line: 3.Qe6+ Kc6 4.Qd5+ Kb6 5.Rf7 Qh4 6.Kf1 Rh1+ 7.Ke2 Qg3 8.Rf3 Qxg2+
>>9.Rf2 Qxg4 10.Kd3 Rb8 -+
>>
>>This is not supposed to be an analysis but 2...Qh8 looks at least very
>>promising.
>
>Ok, but I think I can keep draw with 2 ... Qh8. 8 Rf3 is a horrible move.
>better seems to be: 8. d4 Re1+ 9. Kd2 Rh8 10. Kc2 Rxc1+ 11. Kb3 bxc3.
>
>I think black can keep a small advantage with Ed's variation


That is funny, 2. ..Qh8 is also the move that Q5T stubbornly wants to keep
playing.

It has no trouble choosing 1. ..Rxh2 2.Rf6 at four ply deep although Rxh2 is
only the 24th move it tries at that depth. It switches back to 1. ..Qg8 a few
times. But its second move in the line from the rootposition is at the moment
still 2. ..Qh8


Game begin

00:00  04.24  -0.62  1..Rxh2 2.Rxf6 Qh8 3.Qe6+ Kd8 4.Rf1 Rh1+
00:00  05.00  0.46  1..Rxh2 2.Rxf6 Qh8 3.Qe6+ Kd8 4.Rf1 Rh1+ 5.Kf2
00:02  06.00  0.05  1..Rxh2 2.Rxf6 Qh8 3.Qe6+ Kd8 4.Rf1 Rh6 5.Qc4 Rh1+
00:03  07.00  -0.81  1..Rxh2 2.Kxh2 Nxg4+ 3.Kg1 Qh8 4.Rf7 Qh2+ 5.Kf1 Qh1+ 6.Ke2
c6 7.Qd1 Qxg2+ 8.Ke1
00:05  07.02  -0.57  1..Qg8 2.Qxg8 Raxg8 3.h3 Nxe4 4.cxb4 Rf8 5.Rxf8 Rxf8 6.d3
Nf2
00:09  08.00  -0.36  1..Qg8 2.Qxg8 Raxg8 3.d3 d5 4.exd5 Bc5+ 5.d4 exd4 6.c4 Nxg4
7.Rf7+
00:12  08.01  -0.36  1..Rxh2
00:24  09.00  -0.38  1..Qg8 2.Qxg8 Raxg8 3.h3 Nxe4 4.cxb4 Rb8 5.b5 Ng3 6.Rf2 Ne4
7.Rf7 axb5
00:32  09.01  -0.38  1..Rxh2
00:58  10.00  -0.38  1..Qg8 2.Qxg8 Raxg8 3.h3 bxc3 4.Nxc3 d5 5.d3 Nxg4 6.Nxd5
Bc5+ 7.Kh1 Nf2 8.Kh2 Nxd3
01:24  10.01  -0.38  1..Rxh2
04:28  10.01  -0.38  1..Rxh2
04:33  10.01  1.27  1..Rxh2 2.Kxh2 Nxg4+ 3.Kg1 Qh8 4.Rf7 Qh2 5.Kf1 Qh1+ 6.Ke2
Qxg2+ 7.Kd3 Rh8
11:03  11.00  1.73  1..Rxh2 2.Rxf6 Qh8 3.Qe6+ Kc6 4.Qd5+ Kb6 5.Rf7 Rh1+ 6.Kf2
Qh4+ 7.Ke2 Qg3 8.Rf3
42:46  12.00  1.87  1..Rxh2 2.Rxf6 Qh8 3.Qe6+ Kc6 4.Qd5+ Kb6 5.Rf3 Qh4 6.Kf1


After entering 1. ..Rxh2 the reply 2.gxf6 is in the list for a while but then it
is back to 1. ..Qh8.

Last Move : 1.Rxf6 (Black to play) (A small bug probably somewhere in the PGN
handling of the analysis window , it should say 2.Rxf6)

00:00  05.00  0.13  2..Qh8 3.Qe6+ Kd8 4.Rf1 Rh1+ 5.Kf2
00:01  06.00  1.81  2..Qh8 3.Qe6+ Kd8 4.Rf7 Rh1+ 5.Kf2 Qh4+ 6.Ke2
00:01  07.00  1.81  2..Qh8 3.Qe6+ Kd8 4.Rf7 Rh1+ 5.Kf2 Qh4+ 6.Ke2 Qe1+ 7.Kd3
00:03  08.00  0.00  2..Qh8 3.Qe6+ Kc6 4.Qd5+ Kd7 5.Qe6+ Kc6 6.Qd5+ Kd7
00:07  09.00  0.00  2..Qh8 3.Qe6+ Kc6 4.Qd5+ Kd7 5.Qe6+ Kc6 6.Qd5+ Kd7
00:39  10.00  1.41  2..Qh8 3.Qe6+ Kc6 4.Qd5+ Kb6 5.Rf3 Rh1+ 6.Kf2 Qh4+ 7.Ke2 Ka7
8.Qc6 Qe1+ 9.Kd3
01:48  11.00  1.45  2..Qh8 3.Qe6+ Kc6 4.Qd5+ Kb6 5.Rf3 Rh1+ 6.Kf2 Qh4+
07:50  12.00  1.44  2..Qh8 3.Qe6+ Kc6 4.Qd5+ Kb6 5.Rf3 Rh1+ 6.Kf2 Qh4+
09:33  12.10  1.44  2..gxf6
09:43  12.10  1.60  2..gxf6 3.Kxh2 Qh8+ 4.Kg1 Qh4 5.Kf1 Qh1+ 6.Ke2 Qxc1 7.Qc4
Qxb2
12:33  13.00  1.12  2..gxf6 3.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Rh8 6.Qf1
53:26  13.01  1.12  2..Qh8
41:49  13.01  1.96  2..Qh8 3.Qe6+ Kc6 4.Rf3 Rh1+ 5.Kf2 Qh4+ 6.Ke2

An possible explanation for this can be seen if one enters 2.Rxf6 gxf6; the
lines following that remain much the same in Q5T but the evaluation goes up and
down a lot. At the moment here resolving a fail-high again at the fifteenth ply.
So that means that the position is looking less unfavourable for White again at
fifteen ply evaluation, if Black plays 2. ..gxf6.


Last Move : 2... gxf6 (White to play)

00:00  06.00  1.20  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Qe1+ 6.Qf1
00:00  09.00  0.58  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Rh8 6.Kf1 Qxg4 7.Kf2
00:06  10.00  -1.52  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Kf1 Qh1+ 6.Ke2 Qxc1 7.Qc4 Qxb2
8.Qa2 Qxa2
00:26  11.00  -1.03  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Rh8 6.Kf1 Qh1+ 7.Kf2 Qxc1 8.Ke2
Ke8 9.Qxc7
00:51  12.00  -2.03  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Kf1 Qh1+ 6.Ke2 Rh8 7.Qd5 c6 8.Qc4
08:46  13.00  -1.27  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Rh8 6.Qf1 b3+ 7.Qf5
24:32  14.00  -2.52  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Rh8 6.Qf1 bxc3 7.Qf5+ Ke8
8.Qg6+

If 2. ..Qh8 is playable then that 4.24 line at the top is already reasonably
good.

Just in: fifteenth ply fail-high resolved:

27:15  15.00  -0.98  2.Kxh2 Qh8+ 4.Kg1 Qh4 5.Qc4 Rh8 6.Qf1 d5+ 7.exd5 Qg3 8.d4

This is a bit confusing as the first move number is not correct; it should be
3.Kxh2 Qh8+ 4.Kg1



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