Evaluation Closed Positions

[Henk]

My chess program still thinks this position is equal. Right or wrong ?

[d] r2q1rk1/5pb1/1pn1b1np/p1p1p1p1/2PpP3/P2P1PP1/1PQN2BP/1RB1NRK1 b - - 0 1

Code: Select all

Depth  Value   Time(seconds)   Nodes
 24    0.1280      57.89    27972829   Be6-d7 b2-b3 Qd8-e7 Kg1-f2 Nc6-d8 h2-h3 
 23    0.1280      25.40    12408755   Be6-d7 b2-b3 Qd8-e7 
 22    0.1280      16.67     7963200   Be6-d7 b2-b3 Qd8-e7 
 21    0.1280      10.00     4787204   Be6-d7 b2-b3 Qd8-e7 Kg1-f2 Nc6-d8 h2-h3 Nd8-e6 a3-a4 Rf8-c8 Rf1-h1 Ra8-a7 
 20    0.1152       6.65     3084954   Be6-d7 b2-b3 
 19    0.1152       3.78     1767336   Be6-d7 b2-b3 
 18    0.1152       1.77      839519   Be6-d7 b2-b3 Kg8-h8 Kg1-f2 Rf8-e8 Rf1-h1 f7-f5 h2-h3 
 17    0.1280       0.59      323973   Be6-d7 Kg1-f2 
 16    0.1280       0.39      164949   Be6-d7 Kg1-f2 
 15    0.1280       0.64      253868   Be6-d7 Kg1-f2 Kg8-h8 h2-h3 Bg7-f6 Rf1-h1 Bf6-e7 b2-b3 f7-f5 
 14    0.1024       0.14       67425   Be6-d7 b2-b3 Bg7-f6 Kg1-f2 Bf6-e7 h2-h3 
 13    0.0896       0.14       46963   Be6-d7 b2-b3 Rf8-e8 Rb1-b2 
 12    0.0896       0.14       46074   Be6-d7 b2-b3 Rf8-e8 Rb1-b2 Re8-e6 a3-a4 
 11    0.1024       0.06       20645   Be6-d7 b2-b3 Rf8-e8 
 10    0.1024       0.02       12829   Be6-d7 b2-b3 Rf8-e8 
  9    0.1024       0.02        5268   Be6-d7 b2-b3 Rf8-e8 Rb1-b2 Re8-e6 
  8    0.0896       0.01        6516   Be6-d7 b2-b3 
  7    0.0896       0.00        1144   Be6-d7 b2-b3 
  6    0.0896       0.00        1146   Be6-d7 b2-b3 Rf8-e8 a3-a4 
  5    0.1024       0.00         784   Be6-d7 
  4    0.1024       0.00         501   Be6-d7 
  3    0.1024       0.00         370   Be6-d7 b2-b3 Rf8-e8 
  2    0.0896       0.00         542   Be6-d7 b2-b3 
  1    0.1152       0.00         100   Be6-d7 

[Henk]

Stockfish 6 evaluation:

Code: Select all

 25	+1.37	24.2M	0:16.85	f6 Qd1 Rf7 Nb3 Bf8 Bd2 h5 Nc1 h4 Nc2 a4 Ne2 Rh7 b4 axb3 Rxb3 Bd6 Qb1 Bc7 Rb5 h3 Bh1 Rg7 Re1 Qd7 Qb2
 24	+1.33	18.8M	0:13.00	f6 Qd1 Rf7 Nb3 Bf8 Bd2 h5 Nc1 h4 Nc2 h3 Bh1 a4 b4 axb3 Rxb3 Rb7 Ne2 Qc7 Rb5 Bd6 Qb1 Rf8 Re1 Rf7 Qb2 g4 fxg4
 23	+1.33	17.5M	0:12.02	f6 Qd1 Rf7 Nb3 Bf8 Bd2 h5 Nc1 h4 Nc2 h3 Bh1 a4 Ne2 Bd6 b3 axb3 Rxb3 Rfa7 Rb5 Qc7 Qb1 Rb8 Qb3 Raa8 Rb1
 22	+1.39	14.0M	0:09.62	f6 Qd1 Rf7 Nb3 Bf8 Bd2 h5 Nc1 h4 Ne2 h3 Bh1 Bd6 Qa4 Bd7 Qd1 Qc7 Nc2 Be6 b4 axb4 axb4 Ra2 bxc5 Bxc5
 22	+1.34	9.4M	0:06.52	f6!
 22	+1.33	7.2M	0:04.97	f6!
 22	+1.27	6.9M	0:04.73	f6 Qa4?
 21	+1.33	2.4M	0:01.59	f6 Qd1 h5 Nc2 a4 b3 axb3 Rxb3 h4 Rb5 h3 Bh1 Qc7 Qe2 Ra7 Re1 Rfa8 Rb2 Bd7 Rb5 Bf8 Rb1 Bd6 Rd1 Ra4 Bb2
 20	+1.33	2.1M	0:01.41	f6 Qd1 h5 Nc2 a4 b3 axb3 Rxb3 h4 Rb5 h3 Bh1 Qc7 Qe2 Ra7 Re1 Bd7 Rb1 Rfa8 Bb2 Bf8 Qf1 Be6
 19	+1.22	674462	0:00.44	f6 Qd1 h5 b3 Rf7 Nc2 Bf8 Bb2 h4 a4 Rh7 Qe2 Qd7 Rfd1 hxg3 hxg3 Rh8 Kf1 Rc8 Na3 Rh2 Nb5 Nb4 Re1
 18	+1.25	365162	0:00.24	f6 Qd1 h5 b3 Rf7 Nc2 Bf8 Bb2 h4 a4 Rh7 Qe2 Qd7 Rfd1 Ra7 Na3 hxg3 hxg3 g4 fxg4
 17	+1.19	185211	0:00.12	f6 Qd1 h5 b3 h4 Nc2 h3 Bh1 Qd6 Bb2 Ra7 Re1 Re7 Qe2 Qc7 Ra1 Rfe8 a4 Qd6 Rad1
 16	+1.23	141249	0:00.10	f6 Qd1 h5 b3 h4 Nc2 h3 Bh1 Qd6 Bb2 Ra7 Re1 Rc7 Qe2 Re8 a4 Rf7 Rf1 Ree7 Rbe1
 15	+1.20	102004	0:00.07	f6 Qd1 h5 b3 h4 Nc2 h3 Bh1 Qd6 Bb2 Ra7 Re1 Rc7 Qe2 Rff7 Rbd1
 14	+1.13	79446	0:00.06	h5 Qd1 h4 b3 h3 Bh1 Qe7 Nc2 Bc8 Bb2 Bb7 Rf2 Qd7 Qe2 f6 Re1 Rad8
 13	+1.15	50009	0:00.04	h5 Qd1 h4 b3 h3 Bh1 Qe7 Nc2 Bc8 Bb2 Bb7 a4 Qd6 Re1
 12	+1.17	18156	0:00.02	h5 Qd1 f6 b3 h4 Nc2 h3 Bh1 Qe7 a4 Rab8 Bb2 Rf7
 11	+1.15	8814	0:00.01	h5 Qd1 h4 b3 h3 Bh1 f5 exf5 Bxf5 Ne4 Bxe4 dxe4
 10	+1.15	7536	0:00.01	h5 Qd1 h4 b3 h3 Bh1 f5 exf5 Bxf5 Ne4 Bxe4 dxe4
  9	+1.14	4446	0:00.00	h5 Qd1 h4 b3 h3 Bh1 Qe7 Nc2 Bc8 Bb2
  8	+1.24	1795	0:00.00	h5 Qd1 h4 Rf2 f6 Nc2 h3 Bf1
  7	+1.21	1040	0:00.00	h5 Qd1 f6 b3 Rf7 Qe2 h4
  6	+1.23	640	0:00.00	h5 Qd1 h4 Rf2 h3 Bf1
  5	+1.28	376	0:00.00	h5 Qa4 Qd6 Qd1 f6
  4	+1.28	286	0:00.00	h5 Qa4 Qd6 Qd1 f6
  3	+1.28	180	0:00.00	h5 Qd1 f6
  2	+1.28	119	0:00.00	h5 Qd1
  1	+1.28	43	0:00.00	h5

I also think white's position is hopeless. So a bug or mis-evaluations or bad search algorithm in my chess program. Has something to do with space I think.

[PK]

Most likely it is a search issue - you need some search to see that white cannot untangle. But if You modify the root position, moving a knight from d2 to e2, then suddenly it becomes almost equal, because f3-f4 works. It is not eval's job to know it.

[Henk]

I still don't understand why this position is not given a higher score like +20 or so.

[Ralf Müller]

In this cases I check it with depth 0 or depth 1 to understand the evaluation.