Author: David Rasmussen
Date: 01:03:35 12/02/02
Go up one level in this thread
On December 01, 2002 at 18:34:09, Roy Eassa wrote:
>
>OK, I think I see now. A brief analysis:
>
>1.Qe6!
>
> [1.Nd8 h6 2.Ne6 Ne8 3.Qf8+ Kh7 4.Qf4 Qc3 5.Rc1 Qb2 6.Kg2 Nf6 7.Qxb8 Qxc1
> 8.Qxa7 Nh5 9.Qf7 Qc8 10.Qf5+ Kh8 11.Nxg7 Qxf5 12.Nxf5 Nf4+ 13.Kg3 Ne2+
> 14.Kg4 Nc3 15.Nxh6 b5 +-]
>
>1...h5 2.Ng5+ Kh8 3.Qf5! Qxa2
>
> [3...Kg8 4.Re7 Qb4
> (4...h4 5.Kg2 Qc1 6.h3 Qc5 7.Rxg7+ Kxg7 8.Ne6+ +-)
> 5.Rxa7 Qe1+ 6.Kg2 Qe8 7.Ne6 Nd7 8.Qd5 +-]
>
>4.Re7 Qa3 5.Rf7 Kg8 6.h4! Rf8
>
Several times along this analysis, Chezzz finds the right move (although not at
the beginning, in reasonable time). But this move seems to be a key move for
Chezzz. It has a hard time finding Re7. It prefers Qg6 here for a long time.
Maybe if Re7 was more obvious for Chezzz in this position, the solution to the
original position would be easier to find. So I think that this makes a good
test position (at least for amateurs):
[D]1r5k/p5p1/1p3n2/5QNp/8/5P2/q4P1P/4R1K1 w - - 0 4
Chezzz actually prefers Re6 here, but it seems that this has a lot to do with
hashing. If I search for some time (say, a minute) and stop the search, and then
redo the search (without clearing the hashtable) Re7 is sometimes found
immediately. This sort of behavior I've seen before, and it annoys me. I don't
know if it's a bug or what. I suspect that it is a common hashing/null
move/repetition/whatever problem.
time nodes depth score pv
00:00:00.14 77kn 06/11/12 -1.465 4. Qe5 Rd8 5. Ne4 Rd5
6. Qe6 Nd7
00:00:00.21 122kn 06/13/13 -1.220 4. Re7 Qa1+ 5. Kg2 Qa3
6. Nf7+ Kg8 7. Nh6+ gxh6
8. Qxf6
00:00:00.29 165kn 06/14/14 -1.187 4. Qg6!
00:00:00.40 225kn 06/14/14 -0.425 4. Qg6 h4 5. Re7 Qa1+
6. Kg2 h3+ 7. Nxh3 Nd5
00:00:00.43 234kn 06/14/14 ---------------------------------------------------
00:00:00.54 303kn 07/15/15 -0.205 4. Qg6 h4 5. Re7 Qa1+
6. Kg2 h3+ 7. Nxh3 Rg8
8. Ng5
00:00:00.64 337kn 07/15/15 ---------------------------------------------------
00:00:01.06 572kn 08/17/17 +0.000 4. Qg6 h4 5. Re7 Qa1+
6. Kg2 h3+ 7. Kxh3 Qf1+
8. Kg3 Qg1+ 9. Kh3 Qf1+
00:00:01.17 625kn 08/17/17 ---------------------------------------------------
00:00:01.68 930kn 09/19/22 +0.000 4. Qg6 h4 5. Re7 Qa1+
6. Kg2 h3+ 7. Kxh3 Qf1+
8. Kg3 Qg1+ 9. Kh3 Qf1+
00:00:02.37 1292kn 09/20/22 ---------------------------------------------------
00:00:03.62 2066kn 10/22/23 +0.000 4. Qg6 h4 5. Re7 Qa1+
6. Kg2 h3+ 7. Kxh3 Qf1+
8. Kg3 Qg1+ 9. Kh3 Qf1+
00:00:09.93 5511kn 10/23/24 ---------------------------------------------------
00:00:13.56 7614kn 11/26/26 +0.000 4. Qg6 Qa3 5. Nf7+ Kg8
6. Nh6+ Kh8 7. Nf7+
00:00:43.73 24Mn 11/26/27 +0.333 4. Re6!
00:01:50.70 58Mn 11/28/28 +1.160 4. Re6 Kg8 5. Kg2 Qd5
6. Rxf6 Qxf5 7. Rxf5 a6
8. Ne4 h4 9. Re5
00:01:58.87 63Mn 11/28/28 ---------------------------------------------------
00:02:22.67 74Mn 12/27/30 +1.085 4. Re6 Kg8 5. Kg2 Qd5
6. Rxf6 Qxf5 7. Rxf5 a6
8. Ne4 g6 9. Re5 a5
00:02:33.21 80Mn 12/27/30 ---------------------------------------------------
force:44.06 86Mn 13/29/30 1/41 4. Re6
Time used: 00:02:45.37
nps: 525234 nodes: 86863298 Q-nodes: 2538298 (2%)
move order: 95%
hash probes: 20649151 hash hits: 6194318 (29%) hash usage: 95%
pawn hash probes: 41198561 pawn hash hits: 41190951 (99%)
EGTB probes: 22
Chezzz also have problems finding 6. h4! quickly :
time nodes depth score pv
00:00:00.14 72kn 06/13/13 +0.710 6. Kg2 Qa5 7. Rxf6 Qxf5
8. Rxf5 a5
00:00:00.21 93kn 06/14/14 ---------------------------------------------------
00:00:00.22 98kn 07/10/10 +1.043 6. Kg2!
00:00:00.25 117kn 07/15/15 +1.085 6. Kg2 Qa5 7. Rxf6 Qxf5
8. Rxf5 a6 9. Rf7
00:00:00.33 144kn 07/15/15 ---------------------------------------------------
00:00:00.36 159kn 08/17/18 +1.010 6. Kg2 Qa5 7. Rxf6 Qxf5
8. Rxf5 a6 9. Rf7 a5
00:00:00.50 211kn 08/17/18 ---------------------------------------------------
00:00:00.55 243kn 09/15/16 +1.343 6. Kg2!
00:00:00.96 510kn 09/20/20 +1.580 6. Kg2 Qa5 7. Rb7 Qxf5
8. Rxb8+ Ne8 9. Rxe8+ Qf8
10. Rxf8+ Kxf8 11. Ne6+ Kf7
12. Nf4 g6
00:00:02.16 1158kn 09/20/23 ---------------------------------------------------
00:00:02.83 1589kn 10/22/22 +1.605 6. Kg2 Qa5 7. Rb7 Qxf5
8. Rxb8+ Ne8 9. Rxe8+ Qf8
10. Rxf8+ Kxf8 11. Ne6+ Kf7
12. Nf4 h4 13. Nd5
00:00:03.80 2054kn 10/22/23 ---------------------------------------------------
00:00:04.69 2582kn 11/24/24 +1.450 6. Kg2 Qa5 7. Rb7 Qxf5
8. Rxb8+ Ne8 9. Rxe8+ Qf8
10. Rxf8+ Kxf8 11. Ne6+ Kf7
12. Nf4 a5 13. Nxh5 b5
00:00:25.42 14Mn 11/25/28 +1.650 6. Rc7 Qd6 7. Rxa7 Qd1+
8. Kg2 h4 9. Qg6 h3+
10. Nxh3 Ne8 11. Qf7+ Kh7
12. Ng5+ Kh6 13. Ne4
00:00:32.52 18Mn 11/26/28 +1.938 6. h4!
00:02:18.96 71Mn 11/28/28 +3.340 6. h4 Rf8 7. Rxf6 Rxf6
8. Qh7+ Kf8 9. Qh8+ Ke7
10. Qxg7+ Kd6 11. Qxf6+ Kd5
12. Qd8+ Kc4 13. Qg8+ Kb4
14. Qf8+ Ka4 15. Qe8+ b5
16. Qxh5
00:02:19.06 71Mn 11/28/28 ---------------------------------------------------
Something to work with... :)
/David
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