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Subject: Re: To ?? or to !!

Author: Dann Corbit

Date: 20:55:11 12/18/00

Go up one level in this thread


On December 18, 2000 at 22:59:33, Laurence Chen wrote:

>This position has bothered the most for the longest time, it was fascinating to
>see that the chess engines I used to analyse this position gives a ? or ?? for
>Black's move 26. ... Bg7.  Eric Schiller awarded this move !!, Fritz awarded ??,
>so the $64.00 question, who is right? The position is listed below before
>Black's 26. ... Bg7
>[D]r5k1/ppp4p/3p3b/3Pn3/1n1KP1p1/1P3rP1/PBB1N2R/R2Q4 b - - 0 26
>
>Now Fritz 6, and Gambit Tiger like the move 26. ... c5+, when I play the move
>26. ... Bg7, both engines think that White can save this position, can this
>position be really saved after 26. ... Bg7?
>
>[D]r5k1/ppp3bp/3p4/3Pn3/1n1KP1p1/1P3rP1/PBB1N2R/R2Q4 w - - 0 27
>
>This position seems to be a tough nut to crack.  It could be one of those
>positions which humans are better than chess engines in tactics !!!

For your proposed solution, the programs I tried respond with Ng1, yeilding a
drawish score.  Here is Phalanx:

r5k1/ppp3bp/3p4/3Pn3/1n1KP1p1/1P3rP1/PBB1N2R/R2Q4 w - -
  4    349    95    79195  Bb2-c3
  4 ->   0:01.06    91493   0 turns
  5    349   147   149236  Bb2-c3  ??
  5    289   235   285004  Bb2-c3
  5 ->   0:02.89   364171   0 turns
  6    289   345   435133  Bb2-c3  ??
  6 -29996   588   813326  Bb2-c3  Pb7-b5  Bc3xb4  Ne5-c6
  6 -29991   707   997964  Rh2xh7  !
  6    -20  1194  1788638  Rh2xh7  Kg8xh7  Bb2-c3  Pc7-c5  Pd5xc6  Ne5xc6
                           Kd4-c4  Pb7-b5  Kc4xb5  Bg7xc3  Ne2xc3  Rf3xc3
  6 ->   0:19.78  2971236   1 turn
  7    -20  2513  3796818  Rh2xh7  ??
  7   -137  4445  6970983  Rh2xh7  Kg8xh7  Ne2-c3  Pc7-c5  Pd5xc6  Ra8-c8
                           Pc6-c7  Rc8xc7  Pa2-a3
  7   -132  7931 12485760  Ne2-g1  !
  7    -78 10975 17307703  Ne2-g1  Pc7-c5  Pd5xc6  Ne5-d3  Kd4-c4  Pb7-b5
                           Kc4xb5  Ra8-b8  Kb5-a4  Nd3xb2  Ka4-a3  Nb2-c4
                           Ka3-a4
  7 ->   1:51.48 17552711   1 turn
  8    -82 21702 34180177  Ne2-g1  Pc7-c5  Pd5xc6  Ne5-d3  Kd4-c4  Pb7-b5
                           Kc4xb5  Ra8-b8  Kb5-a4  Nd3xb2  Ka4-a3  Nb2-c4
                           Ka3-a4  Nc4-b6  Ka4-a3  Nb6-c4
  8 ->   3:39.84 34591997   0 turns
  9    -82 56054 86434387  Ne2-g1  Pc7-c5  Pd5xc6  Ne5-d3  Kd4-c4  Pb7-b5
                           Kc4xb5  Ra8-b8  Kb5-a4  Nd3xb2  Ka4-a3  Nb2-c4
                           Ka3-a4  Nc4-b6  Ka4-a3  Nb6-c4
  9 ->   9:50.55 90779427   0 turns
Depth=10, Value=-82, Time=999.02, Last turn=79.31, Nodes=150955328, N/s=151103
PV = Ne2-g1  Pc7-c5  Pd5xc6  Ne5-d3  Kd4-c4  Pb7-b5  Kc4xb5  Ra8-b8
     Kb5-a4  Nd3xb2  Ka4-a3  Nb2-c4  Ka3-a4  Nc4-b6  Ka4-a3  Nb6-c4

Here is crafty:

       clearing hash tables
       time surplus   0.00  time limit 166:39 (166:39)
  nss  depth   time  score   variation (1)
         4     0.23   4.60   1. Qd2 c5+ 2. dxc6 Nexc6+ 3. Kc4 Bxb2
                             4. Qg5+ Kh8 5. Rb1
         4     0.29   4.64   1. Rb1 Nd3+ 2. Kc4 Bxb2 3. Bxd3 Nxd3
         4->   0.30   4.64   1. Rb1 Nd3+ 2. Kc4 Bxb2 3. Bxd3 Nxd3
         5     0.44     --   1. Rb1
         5     0.52  -3.12   1. Rb1 c5+ 2. dxc6 bxc6 3. Bd3 Rxd3+
                             4. Qxd3 Nxd3+ 5. Ke3 Bxb2 6. Rf1
         5     0.77     ++   1. Ng1!!
         5     0.91   1.67   1. Ng1 Nd3+ 2. e5 Bxe5+ 3. Kc4 Nxb2+
                             4. Kxb4 Bc3+ 5. Kb5 Nxd1 6. Rxd1
         5     1.10     ++   1. Rh5!!
         5     1.22   3.01   1. Rh5 Nd3+ 2. Kc4 Nxb2+ 3. Kxb4 a5+
                             4. Kb5 Nxd1 5. Rxd1
         5     1.77     ++   1. Rxh7!!
         5->   1.90   3.40   1. Rxh7
         6     1.93     --   1. Rxh7
         6     2.53  -0.45   1. Rxh7 c5+ 2. dxc6 bxc6 3. Rxg7+ Kxg7
                             4. Bd3 Rxd3+ 5. Qxd3 Nbxd3 6. Ba3 Rd8
         6     3.14     ++   1. Ng1!!
         6     3.85   1.57   1. Ng1 Nd3+ 2. e5 Bxe5+ 3. Kc4 Nxb2+
                             4. Kxb4 Bc3+ 5. Ka3 Nxd1 6. Rxd1
         6->   4.97   1.57   1. Ng1 Nd3+ 2. e5 Bxe5+ 3. Kc4 Nxb2+
                             4. Kxb4 Bc3+ 5. Ka3 Nxd1 6. Rxd1
         7     5.23     --   1. Ng1
         7     6.11   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
         7->   9.77   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
         8    13.27   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
         8->  14.52   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
         9    24.85   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
         9->  29.32   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
        10    57.79   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
        10->   1:11   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. Kc4 b5+
                             4. Kxb5 Rb8+ 5. Ka4 Nxb2+ 6. Ka3 Nc4+
                             7. Ka4 Nb2+
        11     3:12   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. e5 Bxe5+
                             4. Kc4 b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+
                             7. Ka3 Nc4+ 8. Ka4 Nb2+
        11->   4:05   0.00   1. Ng1 c5+ 2. dxc6 Nd3+ 3. e5 Bxe5+
                             4. Kc4 b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+
                             7. Ka3 Nc4+ 8. Ka4 Nb2+
        12     9:15   1/29   1. Ng1


Amy:
GamePhase: Middlegame
It    Time   Score  principal Variation
 8     3.0  +0.032  1. Rxh7 c5+ 2. dxc6 bxc6 3. Rxg7+ Kxg7 4. Bd3 Rxd3+ 5.
                    Qxd3 Nbxd3 6. Bc3 Rf8
         8      3     306  536598 1. Rxh7 c5+ 2. dxc6 bxc6 3. Rxg7+ Kxg7 4. Bd3
Rxd3+ 5. Qxd3 Nbxd3 6. Bc3 Rf8
 8     4.2  +0.032  1. Rxh7 c5+ 2. dxc6 bxc6 3. Rxg7+ Kxg7 4. Bd3 Rxd3+ 5.
                    Qxd3 Nbxd3 6. Bc3 Rf8
         8      3     423  746996 1. Rxh7 c5+ 2. dxc6 bxc6 3. Rxg7+ Kxg7 4. Bd3
Rxd3+ 5. Qxd3 Nbxd3 6. Bc3 Rf8
 9    10.7     ---  1. Rxh7
         9      0    1074 2129259 1. Rxh7?
 9    17.5  -0.800  1. Rxh7 Kxh7 2. Ng1 Rxg3 3. Ne2 Nxc2+ 4. Qxc2 Rd3+ 5.
                    Qxd3 Nxd3+ 6. Kxd3 Bxb2 7. Rh1+ Kg6 8. Nd4
         9    -80    1758 3621480 1. Rxh7 Kxh7 2. Ng1 Rxg3 3. Ne2 Nxc2+ 4. Qxc2
Rd3+ 5. Qxd3 Nxd3+ 6. Kxd3 Bxb2 7. Rh1+ Kg6 8. Nd4
 9    35.3     +++  1. Ng1
         9      0    3537 7369503 1. Ng1!
 9    37.1  +0.000  1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4 b5+ 5. Kxb5
                    Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10.
                    Ka4 Nb2+ 11. Ka3 Nc4+ 12. Ka4 Nb2+
         9      0    3714 7793163 1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4
b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10. Ka4 Nb2+
11. Ka3 Nc4+ 12. Ka4 Nb2+
 9    37.3  +0.000  1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4 b5+ 5. Kxb5
                    Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10.
                    Ka4 Nb2+ 11. Ka3 Nc4+ 12. Ka4 Nb2+
         9      0    3732 7824279 1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4
b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10. Ka4 Nb2+
11. Ka3 Nc4+ 12. Ka4 Nb2+
10    1:05  +0.000  1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4 b5+ 5. Kxb5
                    Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10.
                    Ka4 Nb2+ 11. Ka3 Nc4+ 12. Ka4 Nb2+
        10      0    651613693275 1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4
b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10. Ka4 Nb2+
11. Ka3 Nc4+ 12. Ka4 Nb2+
10    1:12  +0.000  1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4 b5+ 5. Kxb5
                    Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10.
                    Ka4 Nb2+ 11. Ka3 Nc4+ 12. Ka4 Nb2+
        10      0    726015258766 1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4
b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10. Ka4 Nb2+
11. Ka3 Nc4+ 12. Ka4 Nb2+
11    2:23  +0.000  1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4 b5+ 5. Kxb5
                    Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10.
                    Ka4 Nb2+ 11. Ka3 Nc4+ 12. Ka4 Nb2+
        11      0   1439530615336 1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4
b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10. Ka4 Nb2+
11. Ka3 Nc4+ 12. Ka4 Nb2+
11    2:50  +0.000  1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4 b5+ 5. Kxb5
                    Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10.
                    Ka4 Nb2+ 11. Ka3 Nc4+ 12. Ka4 Nb2+
        11      0   1705736032249 1. Ng1 c5+ 2. dxc6 Ned3+ 3. e5 Bxe5+ 4. Kc4
b5+ 5. Kxb5 Rb8+ 6. Ka4 Nxb2+ 7. Ka3 Nc4+ 8. Ka4 Nb2+ 9. Ka3 Nc4+ 10. Ka4 Nb2+
11. Ka3 Nc4+ 12. Ka4 Nb2+

Yace:
         8 0.002   4.59  1t : Rh2xh7 Kg8xh7 [510]
        38 0.006   7.41  1t : Ra1c1 Nb4xa2 [810]
        57 0.011   8.31  1t : Qd1d2 [910]
        79 0.016   8.31  1. : Qd1d2 [910]
      1417 0.026   7.79  2--: Bb2c1 Nb4c6+ d5xc6 Ne5xc6+ Kd4d5 Bg7xa1 Rh2xh7
                              [730]
      2123 0.034   4.80  2t : Qd1d2 c7c5+ d5xc6 Ne5xc6+ Kd4c4 Bg7xb2 [580]
      3451 0.045   5.00  2t+: Ra1b1 Ne5d3+ Kd4c4 Bg7xb2 [580]
      3962 0.048   5.20  2t : Ra1b1 Ne5d3+ Kd4c4 Bg7xb2 Bc2xd3 Nb4xd3 [570]
      4388 0.052   5.35  2t+: Bb2c3 c7c5+ d5xc6 Ne5xc6+ Kd4c4 Bg7xc3 Ne2xc3
                              Nb4xc2 [580]
      5022 0.062   7.40  2t : Bb2c3 c7c5+ d5xc6 Ne5xc6+ Kd4c4 Nb4xc2 Qd1xc2
                              Bg7xc3 Ne2xc3 Rf3xg3 [800]
      5160 0.070   7.40  2. : Bb2c3 c7c5+ d5xc6 Ne5xc6+ Kd4c4 Nb4xc2 Qd1xc2
                              Bg7xc3 Ne2xc3 Rf3xg3 [800]
     11832 0.094   7.40  3t : Bb2c3 c7c5+ d5xc6 Ne5xc6+ Kd4c4 Nb4xc2 Qd1xc2
                              Bg7xc3 Ne2xc3 Rf3xg3 [800]
     13964 0.107   7.40  3. : Bb2c3 c7c5+ d5xc6 Ne5xc6+ Kd4c4 Nb4xc2 Qd1xc2
                              Bg7xc3 Ne2xc3 Rf3xg3 [800]
     39113 0.180   6.90  4--: Ra1b1 Ne5d3+ e4e5 Nb4xc2+ Kd4c4 Nd3xb2+ Rb1xb2
                              [570]
     77093 0.255   4.26  4t : Bb2c3 Rf3f1 Kd4e3 Rf1xd1 Bc2xd1 [410]
    121838 0.344   4.27  4t+: Rh2xh7 Ra8e8 Rh7xg7+ Kg8xg7 [840]
    124810 0.353   4.26  4t-: Rh2xh7 Kg8xh7 Bc2d3 Ne5xd3+ Kd4c4 [180]
    124810 0.353   4.26  4t : Bb2c3 Rf3f1 Kd4e3 Rf1xd1 Bc2xd1 [410]
    195936 0.493   4.26  4. : Bb2c3 Rf3f1 Kd4e3 Rf1xd1 Bc2xd1 [410]
    378060 0.740   4.26  5t : Bb2c3 Rf3f1 Kd4e3 Rf1xd1 Bc2xd1 [410]
    424511 0.858   4.26  5. : Bb2c3 Rf3f1 Kd4e3 Rf1xd1 Bc2xd1 [410]
   1026839 1.965   3.76  6--: Bb2c3 Nb4xc2+ Qd1xc2 b7b5 Ra1f1 Rf3xf1 Qc2d3
                              Ne5xd3+ Kd4xd3 [-280]
   1034174 1.983 -Mat02  6t : Bb2c3 b7b5 Bc3xb4 Ne5c6+ [1230]
   1045204 1.998 -Mat03  6t+: Rh2xh7 Kg8xh7 null Nb4xc2+ Qd1xc2 c7c5+ [500]
   2121603 3.647   1.69  6t : Rh2xh7 c7c5+ d5xc6 b7b5 Rh7xg7+ Kg8xg7 Bc2d3
                              Rf3xd3+ Qd1xd3 Nb4xd3 [110]
   4123758 7.154   1.69  6. : Rh2xh7 c7c5+ d5xc6 b7b5 Rh7xg7+ Kg8xg7 Bc2d3
                              Rf3xd3+ Qd1xd3 Nb4xd3 [110]
   6587189 11.45   1.19  7--: Rh2xh7 c7c5+ d5xc6 b7xc6 Rh7xg7+ Kg8xg7 Bc2d3
                              Rf3xd3+ Qd1xd3 Ne5xd3 e4e5 [10]
   7947035 13.16  -0.26  7t : Rh2xh7 c7c5+ d5xc6 b7xc6 Rh7xg7+ Kg8xg7 Bc2d3
                              Rf3xd3+ Qd1xd3 Nb4xd3 Ra1b1 Ra8e8 [10]
  14353564 22.60  -0.25  7t+: Ne2g1 c7c5+ d5xc6 Ne5d3+ Kd4c4 b7b5+ Kc4xb5
                              Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb4xc2+ Rh2xc2 d6d5
                              null Nb2xd1 Ra1xd1 d5xe4 [-10]
  18107407 27.69   0.00  7t : Ne2g1 c7c5+ d5xc6 Ne5d3+ e4e5 Bg7xe5+ Kd4c4
                              b7b5+ Kc4xb5 Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb2c4+
                              Ka3a4 Nc4b2+ [680]
  18184596 27.84   0.00  7. : Ne2g1 c7c5+ d5xc6 Ne5d3+ e4e5 Bg7xe5+ Kd4c4
                              b7b5+ Kc4xb5 Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb2c4+
                              Ka3a4 Nc4b2+ [680]
  33074867 46.67   0.00  8t : Ne2g1 c7c5+ d5xc6 Ne5d3+ e4e5 Bg7xe5+ Kd4c4
                              b7b5+ Kc4xb5 Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb2c4+
                              Ka3a4 Nc4b2+ [680]
  37218240 53.54   0.00  8. : Ne2g1 c7c5+ d5xc6 Ne5d3+ e4e5 Bg7xe5+ Kd4c4
                              b7b5+ Kc4xb5 Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb2c4+
                              Ka3a4 Nc4b2+ [680]
 108594248 143.1   0.00  9t : Ne2g1 c7c5+ d5xc6 Ne5d3+ e4e5 Bg7xe5+ Kd4c4
                              b7b5+ Kc4xb5 Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb2c4+
                              Ka3a4 Nc4b2+ [680]
 120313372 161.2   0.00  9. : Ne2g1 c7c5+ d5xc6 Ne5d3+ e4e5 Bg7xe5+ Kd4c4
                              b7b5+ Kc4xb5 Ra8b8+ Kb5a4 Nd3xb2+ Ka4a3 Nb2c4+
                              Ka3a4 Nc4b2+ [680]



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