Abillo position: Can any engine solve it?

[zullil]

Code: Select all

41    +0.97 11:26:52  351719M Nh4 Bxh4 Rxh4 Rf2 Rh6 Bf3 Rg6 Kf1 Ba6 Nb5 Bh6 
                              Rfb2 Qe7 Nc1 Kh8 Nd3 Rag8 Qe2 Bc8 Ke1 Bg5 Kd1 Bh4 
                              Ra2 Ba6 Qb2 R6g7 Qd2 Re8 Kc2 Qd8 

[zullil]

Code: Select all

42    +0.97 14:09:34  438410M Nh4 Bxh4 Rxh4 Rf2 Rh6 Bf3 Rg6 Kf1 Ba6 Nb5 Bh6 
                              Rfb2 Qe7 Nc1 Kh8 Qa4 Rag8 Nc3 Qc7 Nd3 Bg5 Nf2 

Terminating search.

[Dann Corbit]

Code: Select all

42    +0.97 14:09:34  438410M Nh4 Bxh4 Rxh4 Rf2 Rh6 Bf3 Rg6 Kf1 Ba6 Nb5 Bh6 
                              Rfb2 Qe7 Nc1 Kh8 Qa4 Rag8 Nc3 Qc7 Nd3 Bg5 Nf2 

Terminating search.

Thanks for your analysis.

[Dann Corbit]

Fig. 6.1: Korchnoi vs. Fischer: Black to play

[d]r1bq2k1/p5bp/3p1nnr/P1pPp3/2P1Pp2/1NN2R1P/4B1P1/1R1QB1K1 b - - bm Nh8;

1. ... Nh8

Reviewer Notes:
It's quite remarkable that Fischer was able to produce such a move in a few seconds. Modern chess programs, however, not only do not select that move in a few seconds, but neither do they when given many hours, preferring other alternatives.

I left Gaviota to calculate this when I left home. It chooses Nh8 after 2 minutes and sticked to it. The score is not great though.

Miguel

Code: Select all

+-----------------+
| r . b q . . k n |
| p . . . . . b p |
| . . . p . n . r |
| P . p P p . . . |    Castling: 
| . . P . P p . . |    ep: -
| . N N . . R . P |
| . . . . B . P . |
| . R . Q B . K . | [White]
+-----------------+

undo
analyze
iterative deepening --> start, thread=0
set timer to infinite
        89   1:      0.0    -0.02  Rb8
       396   2:      0.0    -0.00  Rb8 2.Qc2
      1115   3:      0.0    -0.06  Rb8 2.Qc2 Rb4
      3751   4:      0.0    -0.11  Rb8 2.Qc2 Nh4 3.Rf1 Nxg2 4.Kxg2 Bxh3+
                                   5.Kg1 Bxf1 6.Bxf1
     13356   5:      0.1    -0.11  Rb8 2.Qc2 Nh4 3.Rf1 Nxg2 4.Kxg2 Bxh3+
                                   5.Kg1 Bxf1 6.Bxf1
     41721   6:      0.2    -0.11  Rb8 2.Qc2 Nh4 3.Rf1 Nxg2 4.Kxg2 Bxh3+
                                   5.Kg1 Bxf1 6.Bxf1
    142933   7:      0.5    -0.16  Rb8 2.Qc2 Nh4 3.Rd3 Ba6 4.Rdd1 Rb4
    209220   8       0.7    -0.11  Rb8 2.Qc2 Nh4 3.Rd3 Rb4 4.Na2 Rb8
                                   5.Rdd1
    274623   8:      1.0    -0.11  Rb8 2.Qc2 Nh4 3.Rd3 Rb4 4.Na2 Rb8
                                   5.Rdd1
    385134   9       1.3    -0.13  Rb8 2.Qc2 Nh4 3.Rd3 Rb4 4.Nb5 Nxe4
                                   5.Rdd1 f3 6.Qxe4 fxe2 7.Qxe2
    677020   9:      2.1    -0.13  Rb8 2.Qc2 Nh4 3.Rd3 Rb4 4.Nb5 Nxe4
                                   5.Rdd1 f3 6.Qxe4 fxe2 7.Qxe2
   1805176  10       5.4    -0.09  Rb8 2.Rf2 Nh4 3.Bd3 f3 4.g4 Rg6 5.Rfb2
                                   Nxg4 6.hxg4 Rxg4+ 7.Kh1
   2409921  10:      6.9    -0.09  Rb8 2.Rf2 Nh4 3.Bd3 f3 4.g4 Rg6 5.Rfb2
                                   Nxg4 6.hxg4 Rxg4+ 7.Kh1
   5716977  11      15.6    -0.14  Rb8 2.Nd2 Rxb1 3.Qxb1 Nh4 4.Rd3 Qxa5
                                   5.Qb8 Qa6 6.Nb5 Nd7
  14510017  11:     39.3    -0.14  Rb8 2.Nd2 Rxb1 3.Qxb1 Nh4 4.Rd3 Qxa5
                                   5.Qb8 Qa6 6.Nb5 Nd7
  18253273  12      49.1    -0.26  Rb8 2.Nd2 Rxb1 3.Qxb1 Nh4 4.Rd3 Qxa5
                                   5.Qb8 Qa6 6.Nb5 Nd7 7.Qc7
  47766804  12     126.8    -0.11  Nh8 2.Bd3 Nf7 3.Rf2 Rg6 4.Kh1 Ng5 5.Rf1
                                   Rb8 6.Bh4 Rb4 7.Nb5
  56066044  12:    150.0    -0.11  Nh8 2.Bd3 Nf7 3.Rf2 Rg6 4.Kh1 Ng5 5.Rf1
                                   Rb8 6.Bh4 Rb4 7.Nb5
 110130961  13     303.3    -0.09  Nh8 2.Nd2 Nf7 3.Qa4 Rg6 4.Rd3 Bd7 5.Qb3
                                   Qxa5 6.Qb7 Rc8 7.Bh4 Rc7
 160195202  13:    447.0    -0.09  Nh8 2.Nd2 Nf7 3.Qa4 Rg6 4.Rd3 Bd7 5.Qb3
                                   Qxa5 6.Qb7 Rc8 7.Bh4 Rc7
 229196911  14     634.3    -0.15  Nh8 2.Nd2 Nf7 3.Qa4 Rg6 4.Rd3 Bd7 5.Qa1
                                   Rb8 6.Rxb8 Qxb8 7.Bh4 Rh6 8.Qe1 Qb2
 784896344  14:   2102.2    -0.15  Nh8 2.Nd2 Nf7 3.Qa4 Rg6 4.Rd3 Bd7 5.Qa1
                                   Rb8 6.Rxb8 Qxb8 7.Bh4 Rh6 8.Qe1 Qb2
1261236298  15    3387.4    -0.14  Nh8 2.Nd2 Nf7 3.Qa4 Ng5 4.Rd3 Bd7 5.Qa1
                                   Rb8 6.Rxb8 Qxb8 7.Bf2 Rg6 8.Kh1 Nf7
                                   9.Bh4
3688449069  15:   9690.7    -0.14  Nh8 2.Nd2 Nf7 3.Qa4 Ng5 4.Rd3 Bd7 5.Qa1
                                   Rb8 6.Rxb8 Qxb8 7.Bf2 Rg6 8.Kh1 Nf7
                                   9.Bh4
6268879114  16   16453.0    -0.11  Nh8 2.Nd2 Qxa5 3.Na4 Qd8 4.Ra3 Bd7
                                   5.Rb7 Nf7 6.Nc3 a6 7.Nf3 Bc8 8.Rb2 Rg6
                                   9.Nh4 Rg5

The most promising analysis for Nh8 seems to be that of kgburcham using Hiarcs. It also appears that around ply 24 it starts to move forward in a positive manner.

I suspect that there are two or more good moves from this position.
It seems pretty clear that Nh4 also offers an advantage.

[Dirt]

Code: Select all

42    +0.97 14:09:34  438410M Nh4 Bxh4 Rxh4 Rf2 Rh6 Bf3 Rg6 Kf1 Ba6 Nb5 Bh6 
                              Rfb2 Qe7 Nc1 Kh8 Qa4 Rag8 Nc3 Qc7 Nd3 Bg5 Nf2 

Terminating search.

Does that score mean black or white has an advantage?

[zullil]

Code: Select all

42    +0.97 14:09:34  438410M Nh4 Bxh4 Rxh4 Rf2 Rh6 Bf3 Rg6 Kf1 Ba6 Nb5 Bh6 
                              Rfb2 Qe7 Nc1 Kh8 Qa4 Rag8 Nc3 Qc7 Nd3 Bg5 Nf2 

Terminating search.

Does that score mean black or white has an advantage?

Black. The +0.97 indicates that SF thinks the given PV leaves it up about a pawn, and in this position SF is playing Black.

[ernest]

Abillo position...
Do you mean Valentin Albillo ?

[Dann Corbit]

Abillo position...
Do you mean Valentin Albillo ?

Yes, a typographical error on my part.