Test Position 1.Nxb4! followed by Rc7!!

[acase]

Here is a position I made based on the "Greek gift", I basically took a position that I checked to make sure the Greek gift sacrifice worked (which was too easy for computers to solve) and added a few things to make it difficult.
This is a variation on the "Greek gift" theme, it involves two clearance moves (clearing the b1-h7 diagonal with one of the moves being a pretty sacrifice itself) before the Greek gift sacrifice on h7.

The tendancy of most engines here is to play 1.Nf5 which probably does win, however there is a better move that leads to a much nicer win, namely 1.Nxb4! followed by the beautiful 2.Rc7!!

[d]r2q1rk1/pb1nbppp/1p6/1p1p4/1n1N4/3NR3/PBRP1PPP/1B1Q2K1 w - - 0 1

If your engine can't seem to find 1.Nxb4! and is stuck on 1.Nf5 then just manually make the moves 1.Nxb4 Bxb4 (see the fllowing diagram) and see if your engine finds the other clearance move 2.Rc7!!

[d]r2q1rk1/pb1n1ppp/1p6/1p1p4/1b1N4/4R3/PBRP1PPP/1B1Q2K1 w - - 0 2

keep in mind that this one (1.Nxb4!) probably won't be solved in a few minutes, it is going to take some time as there are other moves that work, but are not the best moves.

And before you slam this one as not being a good test position, Robert Basham...just make the first 2 key moves manually and then you'll have an easy one for you.

[zullil]

If your engine can't seem to find 1.Nxb4! and is stuck on 1.Nf5 then just manually make the moves 1.Nxb4 Bxb4 (see the fllowing diagram) and see if your engine finds the other clearance move 2.Rc7!!

[d]r2q1rk1/pb1n1ppp/1p6/1p1p4/1b1N4/4R3/PBRP1PPP/1B1Q2K1 w - - 0 2

OK, Stockfish-1.6.3 (8 threads) can handle the "easy" position, but it takes some time. Not sure it will handle the original position, but I'll set it up and let it run.

Code: Select all

Searching: r2q1rk1/pb1n1ppp/1p6/1p1p4/1b1N4/4R3/PBRP1PPP/1B1Q2K1 w - -
infinite: 0 ponder: 0 time: 0 increment: 0 moves to go: 0
 2     -1.05   00:01      150 Nxb5 a6 
 3     -0.53   00:01      993 Nxb5 Nc5 Qg4 
 4     -0.36   00:01     2280 Nxb5 Bc5 d4 Bb4 
 5     -0.16   00:01     4094 Nxb5 Bc5 d4 a6 dxc5 axb5 cxb6 Qxb6 
 6     -0.61   00:01     7736 Nxb5 Nf6 Rc7 Ba6 Bxf6 Qxf6 
 7     +0.28   00:01    25787 Nxb5 d4 Rg3 Nf6 Rc4 Bc5 Bxd4 
 8     +0.16   00:01    48759 Nxb5 d4 Rg3 Nf6 Rc4 Bc5 Bxd4 Bd5 Rxc5 bxc5 Bxc5 
 9     -0.16   00:01   112936 Nxb5 g6 a3 Be7 Rc7 Ba6 Rxa7 Rxa7 Nxa7 Bd6 
 9     +0.00   00:01   126867 Nf5 Nf6 Rg3 g6 Nh6+ Kg7 Nf5+ Kg8 Nh6+ 
10  >  +0.44   00:01   340364 Nf5 Nf6 Rg3 g6 a3 Bc5 Qf3 Kh8 Nh6 
11     +0.65   00:01   494460 Nf5 Nf6 Rg3 Kh8 Rxg7 Rc8 Rxc8 Bxc8 Rg3 Bxf5 Bxf5 
                              Rg8 Qa1 
12     +0.04   00:01    2215k Nf5 Nf6 Rg3 g6 a3 Bc5 Nh6+ Kg7 Qf3 d4 Nf5+ Kh8 
                              Qxb7 gxf5 Rc1 Qd5 Qxd5 Nxd5 Bxf5 Rfe8 
12     +1.49   00:01    2437k Nc6 Bxc6 Rxc6 f5 Qb3 Nb8 Rce6 Na6 R6e5 Rf7 Rxd5 
                              Qf8 Bxf5 Nc7 
13     +1.82   00:02    3961k Nc6 Bxc6 Rxc6 f5 Qb3 Nb8 Rce6 Bc5 d4 Na6 R6e5 Bd6 
                              Qxd5+ Kh8 Rxf5 Nc7 Rxf8+ Qxf8 Qh5 
14     +2.51   00:02    6468k Nc6 Bxc6 Rxc6 f5 Qb3 Nb8 Rce6 Bc5 d4 Na6 R6e5 Bd6 
                              Rxd5 Kh8 Rxf5 Rxf5 Bxf5 Nc7 Rh3 h6 Qf7 Qg5 
15     +2.42   00:03   10042k Nc6 Bxc6 Rxc6 f5 Qb3 Be7 Qxd5+ Kh8 Rce6 Bf6 d4 
                              Bg5 Re2 Rf6 Qxb5 Rxe6 Rxe6 Nf6 Qxf5 Qd5 
16     +2.55   00:04   15711k Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 
                              Qd7 Bc2 d4 Re5 Kh8 Bd1 d3 Ba3 Qd4 Bb2 
17  <  +2.22   00:05   25570k Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 
                              Qd7 Bc2 d4 Re5 d3 Rexc5 bxc5 Bxd3 a6 Rxa6 Rd8 
18     +2.38   00:09   58655k Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 
                              Qd7 Bc2 d4 Re5 d3 Rexc5 bxc5 Bxd3 a6 Rxa6 Rd8 
                              Qxd7 Rfxd7 Bc4+ Kh8 Be5 Rd1+ Bf1 Re1 Re6 Rb1 
19     +2.38   00:18  125053k Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 d4 
                              Re1 d3 Rd1 Qd7 Rxc5 bxc5 Bxd3 Qxb5 Bxb5 Re7 f4 
                              Rb8 Bc4+ Kf8 Be5 Rb4 Rd8+ Re8 
20     +2.42   00:41  311937k Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 d4 
                              Re1 d3 Rd1 Qd7 Rxc5 bxc5 Bxd3 Rd8 Qxc5 Qa4 Rd2 
                              Qxa2 Bxf5 Rxd2 Qc8+ Rf8 Be6+ Qxe6 Qxe6+ Kh8 Bc3 
                              Rdxf2 
21  <  +2.22   01:32  710653k Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 
                              Qd7 Kf1 a6 
22     +2.26   02:34    1194M Nc6 Bxc6 Rxc6 f5 Qb3 Bc5 d4 Rf7 dxc5 Nxc5 Qxb5 
                              Qd7 Be5 d4 Rg3 Re8 f4 Re6 Rxc5 bxc5 Qxc5 Rc6 Qa3 
                              g6 Bd3 Qd5 Rh3 Rc3 Qb4 Rc1+ Bf1 
22  >  +3.07   06:29    3050M Rc7 Qxc7 Bxh7+ Kxh7 Nf5 Kg8 Qg4 g6 Rh3 Ne5 Qh4 f6 
                              Qh8+ Kf7 Qg7+ Ke8 Qxc7 gxf5 Qxb7 
23     +5.41   17:32    8504M Rc7 Qxc7 Bxh7+ Kxh7 Nf5 Nf6 Bxf6 Kg8 Rg3 Rfd8 
                              Rxg7+ Kf8 g3 Ke8 Qe2+ Kd7 Rxf7+ Kc8 Rxc7+ Kxc7 
                              Be5+ Bd6 Nxd6 Rxd6 Qxb5 Rd8 f4 Bc6 Qb4 a5 Qb2 a4 
                              g4 b5 Bxd6+ Kxd6 Qf6+ Kd7 h4 Re8 Kf2 Re6 Qd4 
24     +5.58   34:01   16574M Rc7 Qxc7 Bxh7+ Kxh7 Nf5 Nf6 Bxf6 Kg8 Rg3 Rfd8 
                              Rxg7+ Kf8 g3 Ke8 Qe2+ Kd7 Rxf7+ Kc8 Rxc7+ Kxc7 
                              Be5+ Bd6 Nxd6 Rxd6 Qxb5 Rd8 f4 Bc6 Qb4 a5 Qb2 a4 
                              g4 b5 Bxd6+ Kxd6 Qf6+ Kd7 h4 Re8 Kf2 Re6 Qf7+ Re7 
                              Qf5+ Kd6 h5 b4 Qf6+ Kd7 
Nodes: 17962148365
Nodes/second: 8117821
Best move: Rc7
Ponder move: Qxc7

[Dann Corbit]

I set the engine to multi-pv of 2 so that I could watch the process. It may have solved faster with that variable set to 1.

Code: Select all

Analysis from C:\test\greekgift.epd   
2/5/2010 4:14:08 PM Level: 7200 Seconds
Analyzing engine: Ivanhoe64 v67a

1) Nxb4; c0 "1.Nxb4! fo 
    Searching move: Nd3xb4, Nd3xb4
    Best move (Ivanhoe64 v67a): Nd4-f5
    Not found in: 2:00:00
      1	00:00	         470	0	-0.14	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8
      1	00:00	         470	0	+0.16	Nd3xb4 Be7xb4 Nd4xb5
   ---------------------------------------------------------------------------
      2	00:00	       2.478	0	-0.04	Nd3xb4 Be7xb4 Nd4xb5 Qd8g5 Rc2c7 d5d4 Rc7xb7 d4xe3 d2xe3
      2	00:00	       2.478	0	+0.35	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8 Qd1g4 Nd3xb2 Rc2xb2
   ---------------------------------------------------------------------------
      3	00:00	       3.953	0	-0.04	Nd3xb4 Be7xb4 Nd4xb5 Qd8g5 Rc2c7 d5d4 Rc7xb7 d4xe3 d2xe3
      3	00:00	       3.953	0	+0.35	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8 Qd1g4 Nd3xb2 Rc2xb2
   ---------------------------------------------------------------------------
      4	00:00	       9.172	0	+0.07	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8 Qd1g4 Nd7f6 Bb2xf6 g7xf6
      4	00:00	       9.172	0	+0.22	Nd3xb4 Be7xb4 Nd4xb5 Bb4c5 d2d4 a7a6 d4xc5 a6xb5
   ---------------------------------------------------------------------------
      5	00:00	      13.017	0	+0.13	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8 Qd1g4 Nd3xb2 Rc2xb2 Qd8c7
      5	00:00	      13.017	0	+0.33	Nd3xb4 Be7xb4 Nd4xb5 Bb4c5 d2d4 a7a6 d4xc5 a6xb5 Qd1g4 Nd7f6
   ---------------------------------------------------------------------------
      6	00:00	      38.140	2.542.000	+0.01	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8 Re3xd3 Qd8xe7 Rc2c7 Rf8e8 Rd3e3
      6	00:00	      38.140	2.542.000	+0.29	Nd3xb4 Be7xb4 Nd4xb5 d5d4 Bb2xd4 Bb4c5 Qd1g4 Nd7f6 Qg4f4 Qd8d5
   ---------------------------------------------------------------------------
      7	00:00	      47.840	1.543.000	+0.39	Nd3xb4 Be7xb4 Nd4xb5 d5d4 Bb2xd4 Bb4c5 Rc2c4 Bc5xd4 Nb5xd4 Qd8g5 Nd4c6 Bb7xc6 Rc4xc6
      7	00:00	      47.840	1.543.000	+0.60	Nd4f5 Nb4xd3 Nf5xe7+ Kg8h8 Re3xd3 Qd8xe7 Rc2c7 Ra8b8 Rd3e3 Qe7b4 Bb2xg7+ Kh8xg7 Re3g3+ Kg7h8 Rc7xd7
   ---------------------------------------------------------------------------
      8	00:00	     323.054	2.584.000	+0.15	Nd3xb4 Be7xb4 Nd4xb5 Nd7f6 Rc2c7 Bb7a6 Bb2xf6 Qd8xf6 Qd1a4 Bb4a5 Re3f3 Ba6xb5 Qa4xb5
      8	00:00	     323.054	2.584.000	+1.68	Nd4f5 Be7g5 Nd3xb4 Bg5xe3 d2xe3 Nd7f6 Bb2xf6 Qd8xf6 Rc2c7 Qf6b2 Rc7xb7 Qb2xb4 Nf5e7+ Kg8h8 Ne7xd5
   ---------------------------------------------------------------------------
      9	00:00	   1.226.494	3.575.000	+0.55	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 Rf8e8 Qd1g4 d5d4 Qg4xd4 Bb4f8 Qd4d3 Nd7f6 Bb2xf6 Qd8xd3 Bb1xd3 g7xf6 Re3g3+ Kg8h8 Bd3xb5
      9	00:00	   1.226.494	3.575.000	+1.63	Nd4f5 Be7g5 Nd3xb4 Bg5xe3 d2xe3 Nd7f6 Bb2xf6 Qd8xf6 Rc2c7 Ra8b8 Nf5e7+ Kg8h8 Qd1d3 g7g6 Qd3xb5
   ---------------------------------------------------------------------------
     10	00:01	   3.489.252	3.996.000	+0.69	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Re3g3 Nd7f6 Bb1xf5 Bb4d6 Rg3e3 b5b4 Qd1c2 Kg8h8 Re3e6 Bd6e7 Bb2xf6 Be7xf6 Rc6d6 b4b3 a2xb3
     10	00:01	   3.489.252	3.996.000	+2.26	Nd4f5 Be7g5 Nd3xb4 Bg5xe3 d2xe3 f7f6 Nb4xd5 Nd7e5 Rc2c7 Bb7xd5 Nf5e7+ Kg8h8 Ne7xd5 Qd8d6 Qd1h5 f6f5
   ---------------------------------------------------------------------------
     11	00:01	   5.615.032	3.999.000	+0.69	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Re3g3 Nd7f6 Bb1xf5 Bb4d6 Rg3e3 b5b4 Qd1c2 Kg8h8 Re3e6 Bd6e7 Bb2xf6 Be7xf6 Rc6d6 b4b3
     11	00:01	   5.615.032	3.999.000	+2.33	Nd4f5 Be7g5 Nd3xb4 Bg5xe3 d2xe3 d5d4 Qd1g4 g7g6 Nf5h6+ Kg8h8 Bb2xd4+ f7f6 Qg4e6 Qd8e8 Qe6xe8 Rf8xe8 Rc2c7 Bb7c8
   ---------------------------------------------------------------------------
     12	00:02	   9.391.315	4.209.000	+1.11	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Nd7b8 Rc6e6 Bb4c5 Re3g3 g7g6 Re6e5 Qd8d7 Re5xd5 Qd7e6 Rd5xf5 Qe6xb3 Rf5xf8+ Bc5xf8 Rg3xb3 Nb8a6 Bb1e4 Ra8d8 Rb3xb5 Na6c7
     12	00:02	   9.391.315	4.209.000	+2.19	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3xe8+ Qd8xe8 d2d4 Nd7f8 Rb2e2 Nf8e6 Qd1d3 Qe8d7 Qd3g3 Ra8c8 Nf5h6+ Kg8f8
   ---------------------------------------------------------------------------
     13	00:04	  16.458.182	4.432.000	+1.07	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Nd7b8 Rc6e6 Bb4c5 Re3g3 g7g6 Re6e5 Qd8d7 Re5xd5 Qd7e6 Rd5xf5 Qe6xb3 Rf5xf8+ Bc5xf8 Rg3xb3 Nb8a6 Rb3xb5 Na6c7 Rb5e5 Ra8d8 d2d4 Kg8f7 Bb1d3 Nc7d5
     13	00:04	  16.458.182	4.432.000	+2.19	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3xe8+ Qd8xe8 d2d4 Nd7f8 Rb2e2 Nf8e6 Qd1d3 Qe8d7 Qd3g3 Ra8c8 Nf5h6+ Kg8f8
   ---------------------------------------------------------------------------
     14	00:04	  19.090.470	4.516.000	+1.07	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Nd7b8 Rc6e6 Bb4c5 Re3g3 g7g6 Re6e5 Qd8d7 Re5xd5 Qd7e6 Rd5xf5 Qe6xb3 Rf5xf8+ Bc5xf8 Rg3xb3 Nb8a6 Rb3xb5 Na6c7 Rb5e5 Ra8d8 d2d4 Kg8f7 Bb1d3 Nc7d5
     14	00:04	  19.090.470	4.516.000	+2.12	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3xe8+ Qd8xe8 Rb2b3 Nd7f6 Rb3e3 Qe8f8 Re3e7 Ra8b8 Bb1d3 a7a5 Nb4c2 Bb7c8 Nc2e3 Bc8xf5 Ne3xf5 Rb8e8
   ---------------------------------------------------------------------------
     15	00:29	 158.371.019	5.472.000	+1.49	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Qb3xb5 a7a6 Qb5b3 f5f4 Re3e1 Bc5f8 Qb3xd5 Nd7f6 Qd5xd8 Ra8xd8 Rc6xb6 a6a5 Re1e5 Rf7c7 Bb1f5 Bf8b4 Bf5e6+
     15	00:29	 158.371.019	5.472.000	+2.27	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2d4 Ne8c7 Ra8d8 Nc7xb5 Qd4c4 Nb5d6 Qc4c7 Nd6xb7 Qc7xb7
   ---------------------------------------------------------------------------
     16	00:33	 179.695.630	5.441.000	+1.56	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Qb3xb5 a7a6 Qb5b3 f5f4 Re3e1 Bc5f8 Qb3xd5 Nd7f6 Qd5xd8 Ra8xd8 Rc6xb6 a6a5 a2a3 a5a4 Bb1c2 Rf7a7 Bc2f5 Ra7c7 h2h3
     16	00:33	 179.695.630	5.441.000	+2.25	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Ra8b8 Ne8d6 Qa1f6 Nd6xb5 d5d4 Re3g3 Nd7c5 Nb5xa7 Rb8e8 Na7b5 Bb7d5 f2f3
   ---------------------------------------------------------------------------
     17	00:36	 198.682.318	5.463.000	+1.56	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Qb3xb5 a7a6 Qb5b3 f5f4 Re3e1 Bc5f8 Qb3xd5 Nd7f6 Qd5xd8 Ra8xd8 Rc6xb6 a6a5 a2a3 a5a4 Bb1c2 Rf7a7 Bc2f5 Ra7c7 h2h3 Bf8e7 Bf5e6+ Kg8h8
     17	00:36	 198.682.318	5.463.000	+2.24	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Ra8b8 Ne8d6 Qa1f6 Nd6xb5 Bb7a6 Qd1a4 Nd7c5 Qa4d4 Qf6xd4 Nb5xd4 Ba6xd3 Bb1xd3 Rb8c8 Bd3e2 Nc5e4
   ---------------------------------------------------------------------------
     18	00:44	 244.426.540	5.505.000	+1.56	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Qb3xb5 a7a6 Qb5b3 f5f4 Re3e1 Bc5f8 Qb3xd5 Nd7f6 Qd5xd8 Ra8xd8 Rc6xb6 a6a5 a2a3 a5a4 Bb1c2 Rf7a7 Bc2f5 Ra7c7 h2h3 Bf8e7 Bf5e6+ Kg8h8
     18	00:44	 244.426.540	5.505.000	+2.21	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Ne8d6 Qa1f6 Nd6xb5 a7a6 Rg3f3 Qf6c6 Nb5d4 Qc6d6 Qd1e2 Ra8c8 Rf3e3 b6b5 f2f4 Kg8g7 Re3e7
   ---------------------------------------------------------------------------
     19	01:00	 336.154.484	5.558.000	+1.53	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Qb3xb5 a7a6 Qb5b3 f5f4 Re3e1 Bc5f8 Qb3xd5 Nd7f6 Qd5xd8 Ra8xd8 Rc6xb6 a6a5 a2a3 a5a4 Bb1c2 Rf7a7 h2h3 Nf6d5 Rb6c6
     19	01:00	 336.154.484	5.558.000	+2.21	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Ne8d6 Qa1f6 Nd6xb5 a7a6 Rg3f3 Qf6c6 Nb5d4 Qc6d6 Qd1e2 Ra8c8 Rf3e3 b6b5 f2f4 Kg8g7 Re3e7
   ---------------------------------------------------------------------------
     20	01:45	 590.098.496	5.611.000	+1.57	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Qb3xb5 a7a6 Qb5b3 f5f4 Re3e1 Bc5f8 Qb3xd5 Nd7f6 Qd5b3 a6a5 a2a3 a5a4 Qb3f3 Qd8d5 Qf3xd5 Nf6xd5 Bb1a2 Ra8d8 Re1e5 Rf7d7
     20	01:45	 590.098.496	5.611.000	+2.11	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Nd7c5 Nd3xc5 b6xc5 Ne8d6 Bb7c6 Nd6xf7 Ra8e8 Nf7g5 Qa1f6 Qd1g4 b5b4 Qg4h4 h7h5
   ---------------------------------------------------------------------------
     21	05:07	1.792.136.494	5.835.000	+1.44	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Bb1d3 Nd7b8 Rc6e6 Nb8d7 d4xc5 Nd7xc5 Qb3xb5 Nc5xe6 Re3xe6 Ra8c8 Re6e5 Rf7e7 Re5xe7 Qd8xe7 Qb5xd5+ Qe7f7 Qd5xf5 Qf7xf5 Bd3xf5 Rc8e8 Kg1f1 g7g6 Bf5c2 Kg8f7 Bc2a4 Re8c8 Ba4b3+ Kf7e7 Kf1e2 b6b5 Ke2e3 a7a5
     21	05:07	1.792.136.494	5.835.000	+2.14	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Nd7c5 Nd3xc5 b6xc5 Ne8d6 Bb7c6 Nd6xf7 Ra8e8 Nf7g5 Qa1f6 Qd1g4 b5b4 Qg4h4 h7h5 Re3xe8+ Bc6xe8 f2f4
   ---------------------------------------------------------------------------
     22	08:50	3.189.356,636	6.015.000	+1.43	Nd3xb4 Be7xb4 Nd4c6 Bb7xc6 Rc2xc6 f7f5 Qd1b3 Bb4c5 d2d4 Rf8f7 Bb1d3 Nd7b8 Rc6e6 Nb8d7 d4xc5 Nd7xc5 Qb3xb5 Nc5xe6 Re3xe6 Ra8c8 Re6e5 Rf7e7 Re5xe7 Qd8xe7 Qb5xd5+ Qe7f7 Qd5xf5 Qf7xf5 Bd3xf5 Rc8e8 Kg1f1 g7g6 Bf5c2 Kg8f7 Bc2a4 Re8c8 Ba4b3+ Kf7e7 Kf1e2 b6b5 Ke2e3 Ke7d7 Bb2d4 Rc8e8+ Ke3f4
     22	08:50	3.189.356,636	6.015.000	+2.19	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Nd7c5 Nd3xc5 b6xc5 Ne8d6 Bb7c6 Nd6xf7 Ra8e8 Nf7g5 Bc6d7 Re3xe8+ Bd7xe8 Qd1e1 Be8d7 Ng5e6 c5c4 h2h3 Qa1f6 Ne6c5 Qf6d6 Nc5xd7 Qd6xd7 Qe1e5 a7a5 h3h4 b5b4 Bb1c2
   ---------------------------------------------------------------------------
     23	49:39	16.948.570,110	5.690.000	+2.18	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Nd7c5 Nd3xc5 b6xc5 Ne8d6 Bb7c6 Nd6xf7 Ra8e8 Nf7g5 Bc6d7 Re3xe8+ Bd7xe8 Qd1e1 Be8d7 Ng5e6
     23	49:39	16.948.570,110	5.690.000	+4.38	Nd3xb4 Be7xb4 Rc2c7 Rf8e8 Rc7xb7 Re8xe3 d2xe3 Nd7f6 Nd4xb5 a7a5 Rb7c7 d5d4 Qd1xd4 Bb4c5 Qd4d3 Qd8xd3 Bb1xd3 Ra8d8 Bd3c2 Nf6e8 Rc7c6 g7g6 Bb2c3 Ne8g7 Bc3xa5
   ---------------------------------------------------------------------------
     24	50:59	17.475.261,011	5.714.000	+2.18	Nd4f5 Be7f6 Nd3xb4 Bf6xb2 Rc2xb2 Rf8e8 Re3g3 g7g6 Nf5d6 Qd8f6 Nd6xe8 Qf6xb2 Nb4d3 Qb2a1 Rg3e3 Nd7c5 Nd3xc5 b6xc5 Ne8d6 Bb7c6 Nd6xf7 Ra8e8 Nf7g5 Bc6d7 Re3xe8+ Bd7xe8 Qd1e1 Be8d7 Ng5e6
     24	50:59	17.475.261,011	5.714.000	+4.38	Nd3xb4 Be7xb4 Rc2c7 Rf8e8 Rc7xb7 Re8xe3 d2xe3 Nd7f6 Nd4xb5 a7a5 Rb7c7 d5d4 Qd1xd4 Bb4c5 Qd4d3 Qd8xd3 Bb1xd3 Ra8d8 Bd3c2 Nf6e8 Rc7c6 g7g6 Bb2c3 Ne8g7 Bc3xa5
   2/5/2010 5:10:54 PM, Time for this analysis: 00:56:42, Rated time: 2:00:00

0 of 1 matching moves
2/5/2010 5:10:55 PM, Total time: 12:56:47 AM
Rated time: 2:00:00 = 7200 Seconds

[zullil]

[d]r2q1rk1/pb1nbppp/1p6/1p1p4/1n1N4/3NR3/PBRP1PPP/1B1Q2K1 w - - 0 1

keep in mind that this one (1.Nxb4!) probably won't be solved in a few minutes, it is going to take some time as there are other moves that work, but are not the best moves.

Well, Stockfish seems to get it but only after a long time!

Code: Select all

Searching: r2q1rk1/pb1nbppp/1p6/1p1p4/1n1N4/3NR3/PBRP1PPP/1B1Q2K1 w - -
infinite: 0 ponder: 0 time: 0 increment: 0 moves to go: 0
 2     -0.89   00:02      704 Nxb4 Bxb4 Nxb5 
 2     -0.81   00:02      950 Nf5 Nxd3 Nxe7+ Kh8 
 3     -0.81   00:02     1371 Nf5 Nxd3 Nxe7+ Kh8 
 4     +0.12   00:02     2527 Nf5 Nxd3 Nxe7+ Kh8 Qh5 
 5     -0.08   00:02     4565 Nf5 Nxd3 Rxe7 Nxb2 Rxb2 Nc5 Qg4 
 6  >  +1.25   00:02     9438 Nf5 Nxd3 Rxe7 Nxb2 Qg4 g6 Rxb2 
 7     +0.57   00:02    19912 Nf5 Nxd3 Nxe7+ Kh8 Rxd3 Qxe7 Rc7 Rfe8 Bxg7+ Kxg7 
                              Rg3+ Kh8 Rxb7 
 8     +1.82   00:02   126826 Nf5 Bg5 Nxb4 Bxe3 dxe3 Nf6 Qd3 a5 Nc6 
 9     +2.99   00:02   182611 Nf5 Bg5 Nxb4 Bxe3 dxe3 Nf6 Bxf6 Qxf6 Rc7 Rab8 
                              Nxd5 Bxd5 Qxd5 Rfd8 Qxb5 
10     +3.35   00:02   363962 Nf5 Bg5 Nxb4 d4 Re1 Nc5 Nxd4 Qd7 Rc1 g6 Nf3 Qg4 
                              Be5 
11     +3.72   00:02    1070k Nf5 Bf6 Nxb4 a5 Bxf6 Nxf6 Re7 Rb8 Nc6 Bxc6 Rxc6 
                              Re8 Rxe8+ Nxe8 Qe2 Nf6 Qxb5 
12     +3.88   00:02    1899k Nf5 Bf6 Nxb4 a5 Bxf6 Nxf6 Re7 Rb8 Nc6 Bxc6 Rxc6 
                              Re8 Rxe8+ Nxe8 Qe2 b4 Qg4 Rb7 Nh6+ Kf8 
13     +3.76   00:03    3593k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Nf6 d4 Re8 Rxe8+ Qxe8 Re2 
                              Qb8 Re5 Qd8 Re7 Qb8 Bd3 a5 
14  <  +3.35   00:03    5971k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rg3 g6 d4 Nf6 Nh6+ Kg7 
                              Qd2 a5 Nd3 Ne4 
15     +3.72   00:04   11195k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rg3 g6 Nd6 Qf6 Nxe8 
                              Qxb2 Nd3 Qa1 Nc7 Rc8 Nxb5 Nc5 Nd6 Rc7 Nxc5 bxc5 
16     +3.56   00:05   18019k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rg3 g6 Nd6 Qf6 Nxe8 
                              Qxb2 Nd3 Qa1 Nd6 Bc6 Nb4 Qf6 Nf5 Kh8 Nh6 Ne5 d4 
                              Nc4 Nxf7+ Kg8 
17     +3.23   00:07   35860k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rg3 g6 Nd6 Qf6 Nxe8 
                              Qxb2 Nd3 Qa1 Re3 Nc5 Nxc5 bxc5 Nd6 Bc6 Nxf7 Re8 
                              Rf3 d4 Rf6 Bd5 Nd6 
18     +3.27   00:13   83972k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rg3 g6 d4 Nf6 Bd3 Ne4 
                              Nh6+ Kg7 Bxe4 dxe4 Qd2 Qd7 Qf4 Rf8 Nf5+ Kh8 Nd6 
                              f6 Re3 a5 
19     +3.27   00:44  335435k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Nd3 
                              Qd8 Rxb5 Rc8 Rb3 Ng6 Ra3 a5 Rb3 Bc6 Bc2 Qf6 Ne5 
                              Ba4 Nxg6 hxg6 
20     +3.35   00:56  422733k Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Nd3 
                              Qd8 Rxb5 Rc8 Rb2 Ne6 Rc2 Rxc2 Bxc2 Qc7 Qd2 Ba6 
                              Nb4 Bc4 Nc6 h6 Nfe7+ Kf8 
21     +3.52   02:13    1034M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Qf8 Bd3 
                              Nf6 Bxb5 g6 Ne3 Qd6 Qb3 Rc8 Qa4 a5 Nd3 Ne4 Rc2 f6 
                              Rxc8+ Bxc8 Qb3 Be6 f3 Nd2 
22     +3.39   03:23    1578M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Qf8 Bd3 
                              Nf6 Bxb5 g6 Ne3 Qd6 Qb3 Rc8 Qa4 a5 Nd3 Ne4 Rc2 
                              Rxc2 Qxc2 Qa3 Qc7 Qxa2 Nf1 Qb1 Ne5 Qxb5 Qxf7+ Kh8 
                              Qxb7 
23     +3.56   05:29    2562M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Qf8 Bd3 
                              Nf6 Bxb5 g6 Ne3 Qd6 Bf1 Rc8 Qa4 a5 Nd3 Ba6 Ne5 
                              Bxf1 Nxf1 Ne4 Qd7 Qxd7 Nxd7 Rc4 Nxb6 Rxd4 Rb5 Nc3 
                              Rxa5 
24     +3.15   19:42    9333M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Re2 
                              Ne6 Re5 Rd8 Qd3 g6 Nh6+ Kg7 Qe3 Qf8 Nd3 Rd6 Bc2 
                              Kh8 Bd1 a5 Bg4 Bc8 a3 f5 Bf3 
25     +3.31   38:55   18358M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Re2 
                              Ne6 Re5 Rd8 Qd3 g6 Nh6+ Kg7 Qe3 Qf8 Nd3 Rd6 Ng4 
                              Qd8 Qh6+ Kg8 Nf4 Nxf4 Qxf4 f6 Re2 Kh8 Bd3 b4 Nh6 
                              Rd7 
26     +3.27 1:30:01   42692M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Re2 
                              Ne6 Re5 Rd8 Nd3 Qf8 Qc1 Kh8 Nf4 g6 Nxe6 fxe6 Nh6 
                              Re8 Bd3 b4 Bb5 Re7 Re1 Qf6 Qe3 a6 Bd3 Re8 
27  >  +3.52 2:18:39   65503M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Re2 
                              Ne6 Re5 Rd8 Bd3 a5 Qg4 g6 Qh4 axb4 Nh6+ Kg7 Ng4 
                              Qf8 Bxg6 fxg6 Rxe6 
28     +3.27 3:40:07  104532M Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8 Rxe8+ Qxe8 d4 Nf8 Re2 
                              Ne6 Re5 Rd8 Bd3 a5 Qg4 g6 Qh4 axb4 Nh6+ Kf8 Rxe6 
                              Qxe6 Qxd8+ Kg7 Ng8 Bc8 g3 Bd7 Ne7 f5 Kf1 Kf7 Ng8 
                              Be8 Nh6+ Kg7 Qg5 
28  >  +4.53 8:34:48  245981M Nxb4 Bc5 Nbc6 Qf6 Qg4 Bxc6 Nxc6 Bxe3 dxe3 
Nodes: 336375641781
Nodes/second: 7980077
Best move: Nxb4
Ponder move: Bc5

[zullil]

[d]r2q1rk1/pb1n1ppp/1p6/1p1p4/1b1N4/4R3/PBRP1PPP/1B1Q2K1 w - - 0 2

Crafty solves the "easy" position:

Code: Select all

Crafty v23.1 (8 cpus)

White(1): hash = 2048M
hash table memory = 2048M bytes.
White(1): setboard r2q1rk1/pb1n1ppp/1p6/1p1p4/1b1N4/4R3/PBRP1PPP/1B1Q2K1 w - - 0 2

       +---+---+---+---+---+---+---+---+
    8  |<R>| . |   |<Q>|   |<R>|<K>| . |
       +---+---+---+---+---+---+---+---+
    7  |<P>|<B>| . |<N>| . |<P>|<P>|<P>|
       +---+---+---+---+---+---+---+---+
    6  |   |<P>|   | . |   | . |   | . |
       +---+---+---+---+---+---+---+---+
    5  | . |<P>| . |<P>| . |   | . |   |
       +---+---+---+---+---+---+---+---+
    4  |   |<B>|   |-N-|   | . |   | . |
       +---+---+---+---+---+---+---+---+
    3  | . |   | . |   |-R-|   | . |   |
       +---+---+---+---+---+---+---+---+
    2  |-P-|-B-|-R-|-P-|   |-P-|-P-|-P-|
       +---+---+---+---+---+---+---+---+
    1  | . |-B-| . |-Q-| . |   |-K-|   |
       +---+---+---+---+---+---+---+---+
         a   b   c   d   e   f   g   h

White(1): st 3600
search time set to 3600.00.
White(1): display stats
display statistics at end of each search.
White(1): display
White(1): go
              time limit 60:00 (+0.00) (60:00)
              depth   time  score   variation (1)
starting thread 1
starting thread 2
starting thread 3
starting thread 4
starting thread 5
starting thread 6
starting thread 7
                8     0.05   0.25   1. Nxb5 g6 2. a3 a6 3. axb4 axb5 4.
                                    Bd4 Re8
                8->   0.05   0.25   1. Nxb5 g6 2. a3 a6 3. axb4 axb5 4.
                                    Bd4 Re8
                9     0.06   0.25   1. Nxb5 g6 2. a3 Be7 3. Rc7 Rb8 4.
                                    Qe2 Re8 5. Bd3
                9->   0.06   0.25   1. Nxb5 g6 2. a3 Be7 3. Rc7 Rb8 4.
                                    Qe2 Re8 5. Bd3
               10     0.13   0.45   1. Nxb5 Bc5 2. d4 Ba6 3. dxc5 Bxb5
                                    4. cxb6 Nxb6 5. Bd4 Re8
               10->   0.14   0.45   1. Nxb5 Bc5 2. d4 Ba6 3. dxc5 Bxb5
                                    4. cxb6 Nxb6 5. Bd4 Re8
               11     0.17   0.43   1. Nxb5 Bc5 2. d4 Bb4 3. Rc7 Ba6 4.
                                    Qc2 Nf6 5. Ba3 Bxa3 6. Nxa3
               11->   0.22   0.43   1. Nxb5 Bc5 2. d4 Bb4 3. Rc7 Ba6 4.
                                    Qc2 Nf6 5. Ba3 Bxa3 6. Nxa3 (s=2)
               12     0.52   0.25   1. Nxb5 Nf6 2. Rc7 Ba6 3. Rxa7 Bc5
                                    4. Rxa8 Qxa8 5. Nc7 Qa7 6. Rg3 Qxc7
                                    7. Bxf6
               12->   0.64   0.25   1. Nxb5 Nf6 2. Rc7 Ba6 3. Rxa7 Bc5
                                    4. Rxa8 Qxa8 5. Nc7 Qa7 6. Rg3 Qxc7
                                    7. Bxf6
               13     1.21   0.04   1. Nxb5 Nf6 2. Bd4 Bc5 3. Bxc5 bxc5
                                    4. Rxc5 Qb6 5. d4 Rac8 6. Rxc8 Rxc8
                                    7. Bd3
               13     1.86   0.38   1. Nf5 Nf6 2. Nxg7 Kh8 3. Bxf6 Qxf6
                                    4. Nh5 Qh6 5. Rc7 Bc8 6. Bd3 d4 7.
                                    Re4
               13->   1.86   0.38   1. Nf5 Nf6 2. Nxg7 Kh8 3. Bxf6 Qxf6
                                    4. Nh5 Qh6 5. Rc7 Bc8 6. Bd3 d4 7.
                                    Re4 (s=2)
               14     2.26   0.33   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Qh5 h6 7. Rh3
                                    Rfe8 8. Qxh6+ Qxh6 <HT>
               14->   2.93   0.33   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Qh5 h6 7. Rh3
                                    Rfe8 8. Qxh6+ Qxh6 <HT> (s=2)
               15     3.50   0.47   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Qh5 h6 7. Rh3
                                    Rfe8 8. Qxh6+ Qxh6 <HT>
               15->   5.78   0.47   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Qh5 h6 7. Rh3
                                    Rfe8 8. Qxh6+ Qxh6 <HT> (s=3)
               16     7.03   0.49   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Qh5 h6 7. Rh3
                                    Rfe8 8. Qxh6+ Qxh6 9. Rxh6+ Kg7 10.
                                    Rh7+ Kf6 (s=2)
               16->  20.53   0.49   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Qh5 h6 7. Rh3
                                    Rfe8 8. Qxh6+ Qxh6 9. Rxh6+ Kg7 10.
                                    Rh7+ Kf6 (s=5)
               17    22.64     +1   1. Nf5!                    
               17    26.33   1.04   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rxc5 bxc5 5. Qc2 Re8 6. Rxe8+ Nxe8
                                    7. Qxh7+ Kf8 8. Qh8+ Ke7 9. Qe5+ Kf8
                                    10. Qxc5+ Qd6 11. Bxd4 Qxc5 12. Bxc5+
                                    Kg8 (s=4)
               17->  38.50   1.04   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rxc5 bxc5 5. Qc2 Re8 6. Rxe8+ Nxe8
                                    7. Qxh7+ Kf8 8. Qh8+ Ke7 9. Qe5+ Kf8
                                    10. Qxc5+ Qd6 11. Bxd4 Qxc5 12. Bxc5+
                                    Kg8 (s=3)
               18    46.47   1.04   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rxc5 bxc5 5. Qc2 Re8 6. Rxe8+ Nxe8
                                    7. Qxh7+ Kf8 8. Qh8+ Ke7 9. Qe5+ Kf8
                                    10. Qxc5+ Qe7 11. Ba3 Qxc5 12. Bxc5+
                                    Kg8 13. Bxd4 (s=2)
               18->   1:20   1.04   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rxc5 bxc5 5. Qc2 Re8 6. Rxe8+ Nxe8
                                    7. Qxh7+ Kf8 8. Qh8+ Ke7 9. Qe5+ Kf8
                                    10. Qxc5+ Qe7 11. Ba3 Qxc5 12. Bxc5+
                                    Kg8 13. Bxd4 (s=4)
               19     1:46   0.87   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rxc5 bxc5 5. Qc2 Re8 6. Rxe8+ Nxe8
                                    7. Qxh7+ Kf8 8. Qh8+ Ke7 9. Qe5+ Kd7
                                    10. Qxc5 Nd6 11. Qxd4 Qg5 12. Nf4 (s=3)
               19->   4:39   0.87   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rxc5 bxc5 5. Qc2 Re8 6. Rxe8+ Nxe8
                                    7. Qxh7+ Kf8 8. Qh8+ Ke7 9. Qe5+ Kd7
                                    10. Qxc5 Nd6 11. Qxd4 Qg5 12. Nf4 (s=6)
               20     4:55     +1   1. Nf5!                    
               20     5:23   1.51   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Bxh7 Qg7 7.
                                    Be4 Bxe4 8. Rxe4 Rfe8 9. Qh5+ Qh7 10.
                                    Bxd4+ Bxd4 11. Qxh7+ Kxh7 12. Rxd4
                                    (s=5)
               20->   8:16   1.51   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Bxh7 Qg7 7.
                                    Be4 Bxe4 8. Rxe4 Rfe8 9. Qh5+ Qh7 10.
                                    Bxd4+ Bxd4 11. Qxh7+ Kxh7 12. Rxd4
                                    (s=8)
               21     9:45   1.30   1. Nf5 Nf6 2. Nxg7 d4 3. Nh5 Bc5 4.
                                    Rc1 Kh8 5. Nxf6 Qxf6 6. Bxh7 Qg7 7.
                                    Be4 Bxe4 8. Rxe4 Rfe8 9. Qh5+ Qh7 10.
                                    Bxd4+ Bxd4 11. Qxh7+ Kxh7 12. Rh4+
                                    Kg6 13. Rxd4 (s=7)
               21    33:52   1.40   1. Rc7 Qxc7 2. Bxh7+ Kxh7 3. Nf5 Nf6
                                    4. Bxf6 Kg8 5. Nh6+ Kh8 6. Rh3 Bc8
                                    7. Ng4+ Kg8 8. Qb1 Qc1+ 9. Qxc1 Bxg4
                                    10. Bxg7 Bxh3 11. Bxf8 Rxf8 12. gxh3
                                    Re8 13. h4
               21->  33:52   1.40   1. Rc7 Qxc7 2. Bxh7+ Kxh7 3. Nf5 Nf6
                                    4. Bxf6 Kg8 5. Nh6+ Kh8 6. Rh3 Bc8
                                    7. Ng4+ Kg8 8. Qb1 Qc1+ 9. Qxc1 Bxg4
                                    10. Bxg7 Bxh3 11. Bxf8 Rxf8 12. gxh3
                                    Re8 13. h4 (s=3)
               22    37:02     +1   1. Rc7!                    
               22    44:44   2.42   1. Rc7 Qxc7 2. Bxh7+ Kxh7 3. Nf5 Nf6
                                    4. Bxf6 Kg8 5. Nh6+ Kh8 6. Rh3 Bc8
                                    7. Ng4+ Kg8 8. Qb1 Qc1+ 9. Qxc1 Bxg4
                                    10. Rh4 Rac8 11. Qb2 Rfe8 12. f3 Bc5+
                                    13. d4 Bd7 14. dxc5 gxf6 15. cxb6 (s=2)
              time=60:00  mat=-2  n=85363892620  fh=74%  nps=23.7M
              extensions=1123.3M qchecks=1582.6M reduced=1506.1M pruned=1441.2M
              predicted=0  evals=3157.5M  50move=0  EGTBprobes=0  hits=0
              SMP->  splits=6627075  aborts=969110  data=94/512  elap=60:00
terminating SMP processes.
White(1): Rc7
              time used:  60:00

[yanquis1972]

so it appears d28+ may be required in non-rybka programs. that's pretty harsh. i let FB (default settings) run to d26 in single-pv mode and aborted.

[GARGAMEL]

Hi Andrew

Here are my results of analysis with SPARC 0.3a!

NN - NN, CCC Forum, Sxb4
r2q1rk1/pb1nbppp/1p6/1p1p4/1n1N4/3NR3/PBRP1PPP/1B1Q2K1 w - - 0 1

Analysis by Spark-0.3a:

1.Sxb4 Lxb4 2.Sc6 Lxc6 3.Txc6 f5 4.Tg3 Tf7 5.Lxf5 Txf5 6.Txg7+ Kf8 7.Txh7
+/= (0.33) Tiefe: 6/7 00:00:00 15kN
+/= (0.35) Tiefe: 8/11 00:00:00 99kN
1.Sf5 Lf6 2.Sxb4 Lxb2 3.Txb2 Te8 4.Tg3 g6 5.Sd6 Df6 6.Sxe8 Dxb2 7.Sd3 Da1 8.Sd6 La6 9.Tf3 Sf6 10.Sb4 De5 11.Sxf7 Kxf7 12.Sxa6
+/- (1.08) Tiefe: 8/15 00:00:00 130kN
+- (2.89) Tiefe: 22/58 00:04:14 4069mN
1.Sxb4! Lxb4 2.Tc7! Dxc7 3.Lxh7+ Kxh7 4.Sf5 Sf6 5.Lxf6 Kg8 6.Tg3 Tfd8 7.Txg7+ Kf8 8.Th7 Ke8 9.De2+ Kd7 10.Txf7+ Kc8 11.De6+ Dd7 12.Txd7 Txd7 13.Le5 a5 14.d4 La3 15.Dxb6 Ta6 16.Dxb5
+- (3.14) Tiefe: 23/58 00:14:28 14579mN
+- (4.28) Tiefe: 23/66 00:26:09 26372mN

regards Anton

[yanquis1972]

or perhaps not.

wow, only d23 in single pv. spark is an odd bird. same as dann corbit's in pv-2. perhaps some MP luck came into play but very impressive.

[Albert Silver]

Great position. A rare bird to find a tactical win that is so hard to spot for today's engines and hardware.

[GARGAMEL]

Hello

again a right solution from DEEP FRITZ 10!

NN - NN, CCC Forum, Sxb4
r2q1rk1/pb1nbppp/1p6/1p1p4/1n1N4/3NR3/PBRP1PPP/1B1Q2K1 w - - 0 1

Analysis by Deep Fritz 10:

1.Sf5 Lf6 2.Sxb4 Lxb2 3.Txb2 Kh8 4.Sxg7 Tg8 5.Sf5 d4 6.Tg3 Df6 7.Dh5 Tg6 8.Sd3 Tag8
+- (1.93) Tiefe: 8/24 00:00:00 284kN
+- (2.48) Tiefe: 21/47 00:18:11 19650mN
1.Sxb4! Lxb4 2.Tc7! Dxc7 3.Lxh7+ Kxh7 4.Sf5 Kg8 5.Dg4 g6 6.Th3 Se5 7.Dh4 f6 8.Dh8+ Kf7 9.Dg7+ Ke6 10.Sd4+ Kd6 11.Sxb5+ Kc6
+- (2.48) Tiefe: 21/52 00:22:07 23783mN
+- (3.96) Tiefe: 22/71 01:11:00 75255mN

regard Anton