Thanks a lot, John!karger wrote:Stockfish-Barracuda x64.... http://www.mediafire.com/?2dp5of6hfardl03

Works well in Deep Fritz13 GUI with rather good speed as for n/s.

As for nullmove: my first impression is, it doesn't use nm less than SF2.3.

Here is one of my favorite test positions as for nm- usage together with easy to be pruned away points near to the root.

It's one of Gerhard Josten's great studies:

[D]2n3B1/6p1/2P2p2/1p3P1p/1p1nK2P/3P4/4N2p/7k w - - 0 1

Code: Select all

```
[Event "?"]
[Site "?"]
[Date "2008.09.11"]
[Round "?"]
[White "Josten"]
[Black "Forum"]
[Result "1-0"]
[SetUp "1"]
[FEN "2n3B1/6p1/2P2p2/1p3P1p/1p1nK2P/3P4/4N2p/7k w - - 0 1"]
[PlyCount "12"]
[EventDate "2008.??.??"]
1. Ke3 (1. Kxd4 $6 Kg2) 1... Nxe2 (1... Kg2 2. Bd5+ Nf3 3. Bxf3+ Kh3 4. Nd4 Nd6
5. c7 Kg3 6. Ke2 Nc8) 2. Kf2 Ne7 (2... Nc3 3. Bb3 Nd6 4. c7 Nc8 5. Kf1 Nb6 6.
Bf7 g6 7. fxg6 Nd1 8. g7 Ne3+ 9. Ke2 Kg1 10. g8=Q+ Ng2 11. Qb8 Nf4+ 12. Kd2 Nc8
13. Qxc8 h1=Q 14. Qg8+ Kh2 15. c8=Q Qf1 16. Kc2 Qxd3+ 17. Kb2 Qe3 18. Qc2+ Kh3
19. Qd1 Kh2 20. Kb1 Qe4+ 21. Qc2+ Qxc2+ 22. Kxc2 b3+ 23. Kxb3 {#16}) (2... Nf4
3. Bb3 g6 4. fxg6 Nd6 5. c7 Ne4+ 6. dxe4 Nd3+ 7. Kf1 Ne5 8. c8=Q Nf3 9. Kf2 Ng1
10. Bd5 Nh3+ 11. Qxh3 b3 12. e5#) 3. c7 (3. Bf7 g6 4. c7 (4. fxg6 $2 Nc3 5. Bb3
Nxc6 6. g7 Ne7) (4. Bb3 gxf5 5. c7 Nc3 6. Kf1 Ncd5 7. Bxd5+ Nxd5 8. c8=Q Ne3+
9. Ke2) 4... Nc3 5. Bb3 gxf5 6. Kf1 Ncd5 7. Bxd5+ Nxd5 8. c8=Q) 3... Nc3 4. Bb3
Nc8 5. Kf1 Ne7 6. Bf7 Nxf5 1-0
```

So I like to start the engine at one of the variants in braces after

1. Ke3 Nxe2 2. Kf2 Ne7 3. Bf7 g6

[D]8/4nB2/2P2pp1/1p3P1p/1p5P/3P4/4nK1p/7k w - - 0 1

There 4.c7 or 4.Bb3 are to be found directly, 4.fxg6? is to be avoided.

Baracuda:

Analysis by Stockfish 2.3B 64bit SSE4.2

8/4nB2/2P2pp1/1p3P1p/1p5P/3P4/4nK1p/7k w - - 0 1

4.fxg6 Sc3 5.g7 Sd1+ 6.Kf1 Se3+ 7.Kf2 Sd1+

= (0.00) Tiefe: 45/53 00:00:05 36382kN

Don't look at time to depth, hash was full already with 5 minutes of computing before, SFBaracuda doesn' find one of the two possible solutions, eval sticks to 0.00 therefore up to depth 45.

Here is SF2.3:

Code: Select all

```
8/4nB2/2P2pp1/1p3P1p/1p5P/3P4/4nK1p/7k w - - 0 1
Analysis by Stockfish 2.3 JA 64bit SSE4.2:
...
4.fxg6 Sc3 5.g7 Sd1+ 6.Kf1 Se3+ 7.Kf2 Sd1+
= (0.00) Tiefe: 38/15 00:00:56 861mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Sb1 7.c8D Sd2+ 8.Kf2 Sxc8 9.Ld5+ Se4+ 10.dxe4 Sb6 11.Lb7 f4 12.e5+
= (0.08 ++) Tiefe: 39/28 00:02:16 2275mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Sb1 7.c8D Sd2+ 8.Kf2 Sxc8 9.Ld5+ Se4+ 10.dxe4 Sb6 11.Lb7 f4 12.e5+
= (0.16 ++) Tiefe: 39/28 00:02:25 2438mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.Ld5+ Sxd5 8.c8D Sec3 9.De6 b3 10.De1 Sd1 11.Ke2+ Kg2 12.Df1+ Kg3 13.Df3+ Kxh4 14.Kxd1 Se3+ 15.Kc1 Sg4 16.d4 f4 17.d5 b4 18.d6
= (0.28 ++) Tiefe: 39/28 00:02:31 2538mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Sxc8 9.Ld5+ Se4+ 10.dxe4 Sb6 11.Lb7 f4 12.e5+
+/= (0.46 ++) Tiefe: 39/68 00:02:39 2651mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Sxc8 9.Ld5+ Se4+ 10.dxe4 Sb6 11.Lb7 f4 12.e5+
+/- (0.73 ++) Tiefe: 39/68 00:02:44 2735mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Sxc8 9.Ld5+ Se4+ 10.dxe4 Sb6 11.Lb7 f4 12.e5+
+/- (1.14 ++) Tiefe: 39/68 00:02:50 2828mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Sxc8 9.Ld5+ Se4+ 10.dxe4 Sb6 11.Lb7 f4 12.e5+
+- (1.75 ++) Tiefe: 39/68 00:02:56 2933mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Se4+ 9.dxe4 Sxc8 10.Ld5 Sb6 11.Lb7 f4 12.e5+
+- (2.67 ++) Tiefe: 39/68 00:03:04 3071mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Se4+ 9.dxe4 Sxc8 10.Ld5 Sb6 11.Lb7 f4 12.e5+
+- (4.04 ++) Tiefe: 39/68 00:03:12 3198mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Se4+ 9.dxe4 Sxc8 10.Ld5 Sb6 11.Lb7 f4 12.e5+
+- (6.09 ++) Tiefe: 39/68 00:03:24 3407mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Se2 7.c8D Sg3+ 8.Kf2 Se4+ 9.dxe4 Sxc8 10.Ld5 Sb6 11.Lb7 f4 12.e5+
+- (9.16 ++) Tiefe: 39/72 00:03:50 3862mN
```

Code: Select all

```
8/4nB2/2P2pp1/1p3P1p/1p5P/3P4/4nK1p/7k w - - 0 1
Analysis by Sting SF 2_VE 64bit:
...
4.fxg6 Sc3 5.c7 Sd1+ 6.Kf1 Se3+ 7.Kf2 Sg4+ 8.Kf1 Se3+
= (0.00) Tiefe: 30/17 00:00:11 107mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
= (0.08 ++) Tiefe: 31 00:00:15 169mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
= (0.16 ++) Tiefe: 31 00:00:17 194mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
= (0.28 ++) Tiefe: 31 00:00:18 209mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
+/= (0.46 ++) Tiefe: 31 00:00:19 219mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
+/- (0.73 ++) Tiefe: 31 00:00:20 237mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
+/- (1.14 ++) Tiefe: 31 00:00:21 250mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
+- (1.75 ++) Tiefe: 31 00:00:22 267mN
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 f4 7.c8L Sxc8 8.Lf7 Se4 9.dxe4 f5 10.exf5 f3 11.Lxh5
+- (2.67 ++) Tiefe: 31 00:00:24 286mN
...
4.c7 Sc3 5.Lb3 gxf5 6.Kf1 Scd5 7.Lxd5+ Sxd5 8.c8D Se3+ 9.Ke2 f4 10.Dc6+ Kg1 11.Df3 h1S 12.Dxf4 Sg2 13.Dxb4 Kh2 14.Dd6+ Kh3 15.De6+ Kg3 16.Kf1 Sxh4 17.De3+ Kg4 18.De4+ Kg5 19.Dxh1 Sf5 20.Dg2+ Kh6 21.Dc6 Kg5 22.Dxb5 Kf4 23.Kf2 Kg4 24.Db4+ Kg5 25.Dd2+ Kg4 26.Dc1 h4 27.Dc4+ Kh3 28.Df4
+- (8.68 ++) Tiefe: 37 00:01:12 930mN
```

Since zugzwang- detection in version 1.6, as fas as I remember, this becomes more and more a leak in search as for zugzwang positions, I think.

Eelco?

Am I right, or could it be due to other pruning techniques too, as for the position shown?