Not logged inRybka Chess Community Forum
Forum RybkaChess Help Search Register Login
Up Topic The Rybka Lounge / Test Positions / WAC.230 revisited yet again
- - By dcorbit (***) [us] Date 2009-07-11 04:45 Upvotes 1
I was wondering about WAC.230, now that we have superior analysis tools at our disposal. Alex Szabo showed a refutation some time ago, and I was trying to confirm his refutation from the root position of WAC.230. Crafty gets his line right up to the passed pawn creation move of 5. Re2! but the score is nowhere near drawlike. This crafty is the last version you can compile with DETECTDRAW (version 20.0).
Code:

Analysis from C:\test\WAC230.EPD   
7/10/2009 8:06:22 PM Level: 3600 Seconds
Analyzing engine: CraftySMP

1) Rb4; id "WAC.230";   
    Searching move: Rb7-b4
    Best move (CraftySMP): Rb7-b4
    identical moves! Found in: 00:00
     12   00:00      1.309.562   9.354.014    0.00   1. ... Rh7 2. Rb1 Kb5 3. Ba3 Rh5 4. f4 a4 5. Bb2 Bd7 6. Ba1 a3 7. Kg4 <HT>
     12   00:00      1.324.010   3.677.805   -1.70   1. ... Rb4 2. cxb4 a4 3. Rb1 c3 4. Rc1 b2 5. Rxc3+ Kd7 6. Rc7+ Kd8 7. Ra7 b1=Q 8. Rxa4
     12   00:00      3.899.320   10.831.444   -1.70   1. ... Rb4 2. cxb4 a4 3. Rb1 c3 4. Rc1 b2 5. Rxc3+ Kd7 6. Rc7+ Kd8 7. Ra7 b1=Q 8. Rxa4
     13   00:00      6.216.277   11.100.494   -2.00   1. ... Rb4 2. cxb4 a4 3. Rb1 Kb5 4. Bc5 c3 5. Rc1 b2 6. Rxc3 b1=Q 7. Ra3 Kc4 8. Rxa4
     13   00:00      7.079.876   11.062.306   -2.00   1. ... Rb4 2. cxb4 a4 3. Rb1 Kb5 4. Bc5 c3 5. Rc1 b2 6. Rxc3 b1=Q 7. Ra3 Kc4 8. Rxa4
     14   00:00      9.500.690   11.047.313   -1.76   1. ... Rb4 2. cxb4 a4 3. Rb1 Kb5 4. Ra1 c3 5. Rc1 c2 6. Kf4 a3 7. f3 a2 8. Rxc2 a1=Q 9. Rxc8 Qxd4+
     14   00:01     12.749.074   11.696.398   -1.76   1. ... Rb4 2. cxb4 a4 3. Rb1 Kb5 4. Ra1 c3 5. Rc1 c2 6. Kf4 a3 7. f3 a2 8. Rxc2 a1=Q 9. Rxc8 Qxd4+
     15   00:01     18.900.899   11.887.357   -2.16   1. ... Rb4!!
     15   00:02     25.623.315   12.811.657   -2.32   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Rc2 bxc2 5. Ba3 c3 6. Kf4 Kc4 7. Ke3 c1=Q+ 8. Bxc1 Kb3 9. Kf4 a3
     15   00:02     28.875.793   14.437.896   -2.32   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Rc2 bxc2 5. Ba3 c3 6. Kf4 Kc4 7. Ke3 c1=Q+ 8. Bxc1 Kb3 9. Kf4 a3
     16   00:03     37.873.722   12.624.574   -2.27   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Rc2 bxc2 5. Ba3 c3 6. Kf4 Kc4 7. Ke3 c1=Q+ 8. Bxc1 Kb3 9. Kf4 a3 10. Be3
     16   00:04     51.677.782   12.919.445   -2.27   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Rc2 bxc2 5. Ba3 c3 6. Kf4 Kc4 7. Ke3 c1=Q+ 8. Bxc1 Kb3 9. Kf4 a3 10. Be3
     17   00:05     75.484.013   12.580.668   -2.34   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Rc2 bxc2 5. Ba3 c3 6. Kf4 Kc4 7. Ke3 c1=Q+ 8. Bxc1 Kb3 9. Kf4 a3 10. Be3 Bd7
     17   00:07     93.196.456   13.313.779   -2.34   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Rc2 bxc2 5. Ba3 c3 6. Kf4 Kc4 7. Ke3 c1=Q+ 8. Bxc1 Kb3 9. Kf4 a3 10. Be3 Bd7
     18   00:21    263.576.580   12.551.265   -2.74   1. ... Rb4!!
     18   00:34    422.594.741   12.429.257   -2.71   1. ... Rb4 2. Rb1 Ra4 3. Rc1 Kb5 4. Kf4 Ra2 5. Ke3 a4 6. f4 Bd7 7. Rh1 Rc2 8. Bb4 b2 9. Rb1 Bc6 <HT>
     18   00:38    478.311.197   12.587.136   -2.71   1. ... Rb4 2. Rb1 Ra4 3. Rc1 Kb5 4. Kf4 Ra2 5. Ke3 a4 6. f4 Bd7 7. Rh1 Rc2 8. Bb4 b2 9. Rb1 Bc6 <HT>
     19   00:51    634.009.656   12.431.561   -3.11   1. ... Rb4!!
     19   01:23   1.034.971.693   12.469.538   -3.27   1. ... Rb4 2. Rb1 Ra4 3. Rc1 Kb5 4. Kf3 Ra2 5. Ke3 a4 6. f3 a3 7. Bb4 Ka4 8. Rb1 Rc2 9. Ra1 a2 10. Kf4 Kb5
     19   01:31   1.135.277.436   12.475.576   -3.27   1. ... Rb4 2. Rb1 Ra4 3. Rc1 Kb5 4. Kf3 Ra2 5. Ke3 a4 6. f3 a3 7. Bb4 Ka4 8. Rb1 Rc2 9. Ra1 a2 10. Kf4 Kb5
     20   02:14   1.662.136.918   12.404.006   -3.13   1. ... Rb4 2. Rb1 Ra4 3. Rc1 Kb5 4. Kf3 Ra2 5. Ke3 a4 6. Bb4 a3 7. Rh1 Ka4 8. Rh8 Ba6 9. Ra8 Kb5 10. Rb8+ Kc6 11. Ra8 Kb6
     20   02:50   2.116.991.815   12.452.893   -3.13   1. ... Rb4 2. Rb1 Ra4 3. Rc1 Kb5 4. Kf3 Ra2 5. Ke3 a4 6. Bb4 a3 7. Rh1 Ka4 8. Rh8 Ba6 9. Ra8 Kb5 10. Rb8+ Kc6 11. Ra8 Kb6
     21   04:34   3.346.270,630   12.189   -3.53   1. ... Rb4!!
     21   09:40   6.866.280,070   11.815   -4.26   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Rb1 Kc4 6. Kf4 Kxd4 7. Rh1 Kd3 8. Rh7 b2 9. Rh1 <HT>
     21   10:53   7.803.996,586   11.933   -4.26   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Rb1 Kc4 6. Kf4 Kxd4 7. Rh1 Kd3 8. Rh7 b2 9. Rh1 <HT>
     22   17:26   12.414.409,879   11.858   -4.50   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Re2 Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kc4 9. Re5 b2 10. e7 Bd7 11. Re1 d4 12. Bxb2 cxb2
     22   21:52   15.801.615,065   12.038   -4.50   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Re2 Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kc4 9. Re5 b2 10. e7 Bd7 11. Re1 d4 12. Bxb2 cxb2
     23   36:36   26.407.851,901   12.025   -4.30   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Re2 Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kc4 9. Re5 b2 10. e7 Bd7 11. Re1 d4 12. Bxb2 cxb2 13. Kf4
     23   56:28   41.449.515,645   12.234   -4.30   1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Re2 Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kc4 9. Re5 b2 10. e7 Bd7 11. Re1 d4 12. Bxb2 cxb2 13. Kf4


Which nearly matches Alex Szabo's line:
Code:

                                              .. Rb4!? 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Re2! Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kd3 9. e7 Bd7 10. Kf3 d4 11. Rh2 Kc4 12. Rh8 b2 13. Rb8 d3 14. Bxb2 cxb2 15. Rxb2 a3 16. Rb7 Be8 17. Ra7 Kb3 18. Ke3 a2 19. Kxd3 Kb2 20. Rb7+ Kc1 21. Ra7
     


Question, can any engine other than Crafty 20.10 find this line and if so, can any engine also come up with a draw score due to white's passed pawn (I do see that Crafty's score has just stared to drop).

For reference, here is some previous WAC.230 analysis form a CCC of yesteryear:
================================================================================
Code:

Author: Alex Szabo

Date: 20:37:36 07/08/02

Go up one level in this thread

--------------------------------------------------------------------------------

On July 08, 2002 at 13:58:27, Miguel A. Ballicora wrote:

>On July 07, 2002 at 15:39:04, Steve Maughan wrote:
>
>>Mike,
>>
>>Is WAC 230 correct?  If I remember corretly there was a discussion here a few
>>months back that said that Rb4 was not such a forced win e.g.
>>
>>http://www.it.ro/ccc_search/ccc.php?art_id=163138
>>
>>Regards,
>>
>>Steve
>
>I still think that WAC230 is a win for black. I did not have time to do an
>analysis and _prove_ it but my intuition tells me so.
>I reproduce the post and answer later.
>
>Subject : WAC 230
>
>----------------------------------------------------------------------------
>Posted by : Bruce Moreland on April 13, 2001 at 04:14:13
>
>This is from a post by Alex Szabo.
>
>#230 [Rb4 does not win. The main line is, 1... Rb4!? 2. cxb4 a4
>3. b5+ Kxb5 4. Ba3 c3 5. Re2! Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kd3
>9. e7 Bd7 10. Kf3 d4 11. Rh2 Kc4 12. Rh8 b2 13. Rb8 d3
>14. Bxb2 cxb2 15. Rxb2 a3 16. Rb7 Be8 17. Ra7 Kb3 18. Ke3 a2
>19. Kxd3 Kb2 20. Rb7+ Kc1 21. Ra7 =]
>
>Ra7, Rb6, Rb5, Rd7, Rf7, Rg7, Rh7, Bd7, Kd7, Kb6, Kb5, a4, and Rc7
>are just as good as the book solution Rb4 -- they all hold the game.
>
>[D]

2b5/1r6/2kBp1p1/p2pP1P1/2pP4/1pP3K1/1R3P2/8 b - - 0 1

>
>I think this is worth thinking about. After 1. ... Rb4 2. cxb4 a5 3. b5+ Kxb5
>4. Ba3 c3 5. Re2 Kc4 6. f4, we get this:
>
>[D]
2b5/8/4p1p1/3pP1P1/p1kP1P2/Bpp3K1/4R3/8 b - - 0 1

>
>6. ... Bd7 is a possibility, but still seems like a draw.
>
>There is some fascinating stuff going on in the main line.
>
>WAC attributes this to Nimzovich, but doesn't give a game reference.
>
>I doubt that the position is solvable by a computer, and if anyone "finds" this,
>they've got some lucky eval terms.
>
>bruce
>-------------------------------------------------------------------------------
>
>The position is from the book "my system", so it is well known from there, not
>from WAC.
>
>IIRC when I looked to this analysis, 6... Bd7 wins. I am "remembering"
>blindfold, so beware. For instance, you can answer 7.f5 with Be8. There is no
>need to give counterchances to white on the king side. Why doing it? White is
>lost in the queen side. One thing is certain, Szabo's move 5. Re2! I is much
>stronger than the "classical" PV (that came from the Nimzovich game).
>
>Regards,
>Miguel
>
>
>> ...


I don't see a win for Black after 6... Bd7.  The best line I can find is: 6...
Bd7  7. f5 Be8!?  8. fxe6 Kxd4  9. e7 Kc4  10. Kf4 d4  11. Rh2 d3  12. Rh8 b2
13. Rxe8 b1=Q  14. Rf8 Rc8+ =.  Please let me know if Black's play can be
improved!

Alex.
Parent - - By dcorbit (***) [us] Date 2009-07-11 04:47
Just in case you don't have it, here is the position being analyzed:
2b5/1r6/2kBp1p1/p2pP1P1/2pP4/1pP3K1/1R3P2/8 b - - bm Rb4; id "WAC.230";


One thing that is totally clear is that with the pawn fortress that white has, the only move with *any* winning chances is Rb4 (even though it seems likely that Rb4 only draws also due to the analysis of Alex Szabo)
Parent - - By Vasik Rajlich (Silver) [pl] Date 2009-07-11 06:25
I always thought it was funny that this position was in the WAC, together with all sorts of simple tactical blows.

Vas
Parent - By Vinvin (***) [be] Date 2009-07-13 02:45
The same from me :-)
Parent - - By dcorbit (***) [us] Date 2009-07-20 19:05
Rybka does find the key move in less than an hour, but I have no pv, so I am not sure what Rybka was thinking.

6) Rb4; id "WAC.230";  
    Searching move: Rb7-b4
    Best move (Rybka 3): Rb7-b4
    identical moves! Found in: 47:49
      2  00:00           131  134.144  +2.37  Rb7f7
      3  00:00           153  156.672  +2.40  Rb7f7
      4  00:00           212  217.088  +2.31  Rb7f7
      5  00:00           323  330.752  +2.35  Rb7f7 f2f4
      6  00:00           481  492.544  +2.35  Rb7f7 f2f4 a5a4
      7  00:00         1.624  103.936  +2.19  Rb7f7 f2f4 Rf7h7 Bd6a3
      7  00:00         2.453  156.992  +2.28  a5a4 Kg3f4 Rb7h7
      7  00:00         3.648  233.472  +2.36  Rb7h7 Kg3f4 Rh7h1 Kf4e3
      8  00:00         5.758  184.256  +2.31  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5
      9  00:00         8.364  267.648  +2.31  Rb7h7 Rb2b1 Rh7h5 Kg3f4 Rh5h2 Kf4g3
     10  00:00        11.539  251.402  +2.31  Rb7h7 Rb2b1 Rh7h5 Kg3g4 a5a4 Bd6a3 Rh5h2 Kg4g3
     11  00:00        16.529  214.249  +2.32  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3f4 Rh7h3 f2f3
     12  00:00        24.297  264.682  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3f4 Rh7h3 f2f3 Rh3h2 Rb1b2
     13  00:00        33.198  241.097  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3f4 Rh7h3 f2f3 Rh3h2 Rb1b2
     14  00:00        47.166  256.904  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3g4 Rh7h5 Kg4f4 Rh5h3
     15  00:00        89.989  267.874  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3g4 Rh7h5 Ba3b2 Rh5h2 Kg4g3 Rh2h7 Bb2a3 Rh7h8
     16  00:00       167.828  289.807  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3g4 Rh7h5 Ba3b2 Rh5h2 Kg4g3 Rh2h7
     17  00:00       197.931  295.023  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3g4 Rh7h5 Ba3b2 Rh5h2 Kg4g3 Rh2h7
     18  00:01       393.492  296.712  +2.46  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Kg3g4 Rh7h5 Ba3b2 Rh5h2 Kg4g3 Rh2h7 Bb2a3 Rh7h8 Ba3d6 Rh8h7 Bd6b4 Rh7h5
     19  00:15     4.276.741  290.294  +2.09  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Rb1g1 Rh7h5 f2f4 Kb5c6 Rg1a1 Rh5h7 Kg3g2 Rh7h4 Kg2g3 Rh4h5 Kg3g2
     20  00:26     6.638.252  261.696  +1.96  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Rb1g1 Rh7h5 f2f4 Kb5a5 Kg3g2 Rh5h4 Kg2g3 Rh4h7 Kg3g2 Rh7b7 Rg1b1
     21  00:48    11.710.332  247.474  +1.87  Rb7h7 Rb2b1 a5a4 Bd6a3 Kc6b5 Rb1g1 Rh7h5 f2f4 Kb5c6 Rg1a1 Bc8d7 Kg3g2 Rh5h4 Kg2g3 Rh4h8 Kg3g2 Rh8b8 Ba3b2 Rb8f8 Kg2f3 Rf8h8 Kf3g2 Rh8a8 Bb2a3
     22  01:09    15.947.930  237.481  +1.88  Rb7h7 Rb2b1 Kc6b5 Bd6a3 Rh7h5 f2f4 Bc8b7 Kg3g2 Rh5h4 Kg2g3 Rh4h8
     23  01:35    21.969.466  237.339  +1.88  Rb7h7 Rb2b1 Kc6b5 Bd6a3 Bc8b7 Kg3g2 Rh7h5 f2f4 Rh5h4 Kg2g3 Rh4h8 Rb1a1
     24  02:29    34.365.949  235.542  +1.82  Rb7h7 Rb2b1 Kc6b5 Bd6a3 Bc8b7 Kg3g2 Rh7h5 f2f4 Rh5h4 Kg2g3 Rh4h7 Rb1a1
     24+  03:39    54.318.157  253.769  +2.08  Kc6b5
     24  04:47    73.548.293  261.978  +1.88  Kc6b5 Rb2b1 Kb5a6 Rb1b2 Rb7h7 Rb2b1 Ka6b6
     25  04:55    75.689.731  262.595  +1.88  Kc6b5 Rb2b1 Kb5a6 Rb1b2 Rb7h7 Rb2b1 Ka6b6
     26  10:01   149.334.222  254.263  +1.82  Kc6b5 Rb2b1 Kb5a6 Rb1b2 Rb7h7 Rb2b1 Ka6b6 Bd6a3
     27  15:36   232.856.126  254.814  +1.82  Kc6b5 Rb2b1 Kb5a6 Rb1b2 Rb7h7 Rb2b1 Ka6b6 Bd6a3
     27+  47:49   807.605.837  288.277  +2.02  Rb7b4
   7/18/2009 8:55:37 AM, Time for this analysis: 01:06:40, Rated time: 47:49
Parent - - By Dadi Jonsson (Silver) [is] Date 2009-07-20 19:34
I went up to depth 30 (2GB hash) without Rybka preferring 1...Rb4. I've also used this as a test position for a beta version of Aquarium (IDeA) and it seems to me that by far the most interesting variations come up after 1... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 (the immediate 4.Re2 leads to transposition) 4...c3 5. Re2 Kc4 6. f4 Kxd4 7. f5 Kd3 (instead of 7...exf5).

[-1.81]  d=30  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 6.Ba3 Bc6 7.Kg2 Rh4 8.Kg3 Rh8 9.Rd1 (0:40.44) 726379kN
[-1.81]  d=29  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 6.Ba3 Bc6 7.Kg2 Rh4 8.Kg3 Rh8 9.Rd1 (0:20.00) 368117kN
[-1.81]  d=28  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 6.Ba3 Bc6 7.Kg2 Rh4 8.Kg3 Rh8 9.Rd1 Kb5 10.Rb1 Rh7 11.Kg2 (0:12.39) 228996kN
[-1.81]  d=27  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 6.Ba3 Bc6 7.Kg2 Rh4 8.Kg3 Rh8 9.Rd1 Kb5 10.Rb1 Rh7 11.Kg2 (0:07.51) 144335kN
[-1.81]  d=26  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 6.Ba3 Bc6 7.Kg2 Rh4 8.Kg3 Rh8 (0:06.17) 116578kN
[-1.81]  d=25  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 6.Ba3 Bc6 7.Kg2 Rh4 8.Kg3 Rh8 (0:03.49) 74170kN
[-1.93]  d=24  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 (0:03.03) 60204kN
[-1.93]  d=23  1...Kb5 2.Rb1 Ka6 3.Rb2 Rh7 4.Rb1 Rh5 5.f4 Bd7 (0:02.58) 58288kN
[-2.12]  d=22  1...Kb5 2.Rb1 Ka6 3.Kf3 b2 4.Ke3 Rb3 5.Kd2 a4 6.Kc2 a3 7.Bxa3 Rxa3 8.Rxb2 Bd7 9.Kd2 Bb5 10.f3 Kb6 11.Rc2 Kc6 12.Rc1 Ba6 13.Rc2 Bb7 (0:01.14) 22584kN
[-2.12]  d=21  1...Kb5 2.Rb1 a4 (0:01.10) 21021kN
[-1.81]  d=21  1...Rh7 2.Rb1 Bb7 3.Ba3 Ba8 4.f4 Kb5 5.Kg2 (0:00.54) 16145kN
[-1.93]  d=20  1...Rh7 2.Rb1 Bb7 3.Ba3 Ba8 4.Kg2 Rh4 5.Rh1 Rg4+ 6.Kf1 Bb7 7.Rh8 Kb5 (0:00.48) 14571kN
[-1.81]  d=20  1...Kb5 2.Rb1 (0:00.42) 12973kN
[-2.40]  d=19  1...Kb5 2.Ba3 Ka4 3.Bd6 Rh7 4.Rb1 Rh5 5.f4 Rh7 6.Kg2 Rb7 7.Rb2 Rf7 8.Kg3 Rh7 9.Rb1 (0:00.10) 2961kN
[-2.44]  d=18  1...Kb5 2.Ba3 Rh7 3.Rb1 (0:00.09) 2504kN
[-2.44]  d=17  1...Rh7 2.Rb1 a4 3.Ba3 Kb5 4.Bb2 Bb7 5.Ba3 Rh5 6.Kg4 Rh2 7.Kg3 Rh5 8.Kg4 Rh2 9.Kg3 Rh5 10.Kg4 Rh2 11.Kg3 Rh5 12.Kg4 Rh2 13.Kg3 Rh5 14.Kg4 Rh2 15.Kg3 Rh5 16.Kg4 Rh2 (0:00.02) 536kN
[-2.44]  d=16  1...Rh7 2.Rb1 a4 3.Ba3 Kb5 4.Bb2 Bb7 5.Ba3 Rh5 6.Kg4 Rh2 7.Kg3 Rh5 8.Kg4 Rh2 9.Kg3 Rh5 10.Kg4 Rh2 11.Kg3 Rh5 12.Kg4 Rh2 13.Kg3 Rh5 14.Kg4 Rh2 15.Kg3 Rh5 16.Kg4 Rh2 (0:00.01) 328kN
[-2.44]  d=15  1...Rh7 2.Rb1 a4 3.Ba3 Kb5 4.Kf4 Bb7 5.Kg4 Rh2 6.Kg3 Rh5 (0:00.00) 204kN
[-2.44]  d=14  1...Rh7 2.Rb1 a4 3.Ba3 Kb5 4.Kf4 Bb7 5.Kg4 Rh2 6.Kg3 Rh5 (0:00.00) 141kN
[-2.44]  d=13  1...Rh7 2.Rb1 a4 3.Ba3 Kb5 4.Kf4 Bb7 5.Kg4 Rh2 6.Kg3 (0:00.00) 97kN
Parent - By Mark (****) [us] Date 2009-07-20 21:30 Edited 2009-07-20 21:35
I've had IDeA (d=15) running on wac230 for a couple days so far.  I'm in Las Vegas now so I can't check, but this morning Rb4 was at -.56.  I had seeded IDeA with a number of lines suggested in other posts.  I'll report back Friday when I get home.  Hopefully, no one at home will shut off Aquarium while I'm gone!  
Parent - - By ernest (****) [fr] Date 2009-07-21 00:49

> I went up to depth 30 (2GB hash) without Rybka preferring 1...Rb4.


1. Maybe in multi-PV you can see that 1...Kb5 and 1...Rb4 are very close
2. There are plenty of factors of non-reproducibility with Dann Corbit: MP, hash, sampled search (Dann uses Arena, so no sampled search)
Parent - By Dadi Jonsson (Silver) [is] Date 2009-07-21 07:41

> 1. Maybe in multi-PV you can see that 1...Kb5 and 1...Rb4 are very close


That wouldn't be surprising. At least IDeA gave seven or eight moves the same evaluation.
Parent - By Vasik Rajlich (Silver) [pl] Date 2009-07-21 05:03
That's a fail-high, you'd need to wait for the iteration to finish.

Vas
Parent - By plicocf (***) [br] Date 2009-07-12 17:44
I don´t know how black can win, it seems that Szabo is rigth.
Parent - - By CSullivan (**) [us] Date 2009-07-24 03:11
Hi Dan,
I spent a couple of days looking at this.  Assuming that 1...Rb4 is the only chance to win, then 2.cxb4 a4 3.b5+ Kxb5 4.Re2 c3 5.Ba3 Kc4 6.f4 Kxd4 7.f5 and now Dadi Jonsson's 7...Kd3 looks best.  After that, the best I can find is 8.fxg6 Kxe2 9.g7 b2 10.g8=Q b1=Q 11.Qxc8 Qg1+ (beginning here, there are many transpositions, but they all end up in the same place) 12.Kh3 Qf1+ 13.Kg4 Qf3+ 14.Kh4 Qe4+ 15.Kh5 Qh7+ 16.Kg4 d4 17.Qc6! (This might be the only move that draws; 17.Qc4+, for instance, allows Black good winning chances).  From here, one line is 17...Qf5+ 18.Kh5 d3 19.Qg2+ Qf2 20.Qe4+ Qe3 21.Qc4 Qh3+ 22.Kg6 c2 23.Kg7 Kd1 24.g6 d2 25.Qxa4 Ke2 26.Qxc2 Qd3 27.Qxd3+ Kxd3=.
Charles
Parent - By Dadi Jonsson (Silver) [is] Date 2009-07-24 07:11

> 17.Qc6! (This might be the only move that draws;


:smile: Yes, this is the key move.
Parent - - By Mark (****) [us] Date 2009-07-25 02:39 Edited 2009-07-25 02:44
I let IDeA run for about 7 days at d=15 on Rb4 (over 17,500 positions).  It has Rb4 at -.29.  Although I seeded IDeA with several lines early on, it ran unassisted for the last 5 days.  I think IDeA did a pretty good job on the position.  The tree includes Charles' line above.  Anyway, here's the IDeA tree for those interested.

edit: I'm not sure why the "-1" was added to the hsh file when I uploaded it??
Attachment: wac230d15.elm (203k)
Attachment: wac230d15.hsh (1k)
Parent - By dcorbit (***) [us] Date 2009-07-27 23:09
Thank you very much for this.
It is a very interesting position to me (and I must confess that it took me an *embarassingly* long time for me to really start to understand it).
Parent - - By dcorbit (***) [us] Date 2009-07-27 23:12
P.S.
I think this has to be a real triumph for the IDEA approach.
I am very sure that no other chess analysis by computer can produce this data in a reasonable time.
Parent - By Mark (****) [us] Date 2009-07-28 02:35
Glad it was helpful, Dan.  The more I use IDeA, the more I like it.  For me it helps keep the analysis of positions like wac230 organized.  I'm looking forward to the IDeA upgrades in Aquarium 4.

I'll be out of town next week and could let it run for another week or so, if you want (either the root position or after Rb4).  If you have any particular lines to add, let me know.

Mark
Parent - - By Dadi Jonsson (Silver) [is] Date 2013-02-28 21:06 Edited 2013-02-28 21:09
Over on Talkchess, George Tsavdaris (who seems to be an endless source of interesting positions) says that after 1...Rb4 2.cxb4 a4 3.b5+ Kxb5 4.Ba3 c3 5.Re2 Kc4 6.f4 Kxd4 7.f5 exf5 8.e6 "...all miss the winning move: ...b2!! wins. So WAC 230 is correct after all".

This is the position:

2b5/8/4P1p1/3p1pP1/p2k4/Bpp3K1/4R3/8 b - - 0 8


Maybe someone should look this up in Mark's analysis. Even at d=15, his three (well, closer to four) year old IDeA analysis might still have a few surprises for today's analysts :smile:
Parent - - By Mark (****) [us] Date 2013-03-01 18:05
I'll see if I can find my old analysis.  I've changed computers since that time and the file isn't on the new one...
Parent - - By Dadi Jonsson (Silver) [is] Date 2013-03-01 19:01
No need for that. The IDeA tree files are attached to your post above :smile:
Parent - By Mark (****) [us] Date 2013-03-01 19:38
Yes, I did see those after my post.  I thought I had run it quite a bit after that time, but I can't find any newer files. 

I haven't used IDeA for a long time, so I have to get familiar with it again.  I may just start things over with maybe d20 and 10 seconds.
Parent - - By George Tsavdaris (****) Date 2013-03-02 11:52
Unfortunately i have discovered that i have made a newer analysis about this and i have found a refutation on ...b2. :sad: Sorry about that. But these are the results of being away from the computer Chess scene for so long, you forget some things. But it is very instructive to follow the variations after b2 since it contains many different types of endgames and tactics. It even contains a crazy queen stalemate! I will post some analysis later on....
Parent - By Mark (****) [us] Date 2013-03-02 13:57
Yes, George, please post the analysis when you have time!
Parent - By Dadi Jonsson (Silver) [is] Date 2013-03-03 11:50
Yes, ...b2 leads to a draw according to Mark's old analysis. It will be interesting to see your analysis. Perhaps there are still some hidden resources in this amazing position.

Here is a snapshot from Mark's analysis tree. I just downloaded it and loaded it into Aquarium. As I said his analysis is a required reading for anyone attempting to analyze this position.
Up Topic The Rybka Lounge / Test Positions / WAC.230 revisited yet again

Powered by mwForum 2.27.4 © 1999-2012 Markus Wichitill