Why most engines can't find this mate in 3 ?

Discussion of anything and everything relating to chess playing software and machines.

Moderators: hgm, Rebel, chrisw

Paloma
Posts: 1167
Joined: Thu Dec 25, 2008 9:07 pm
Full name: Herbert L

Why most engines can't find this mate in 3 ?

Post by Paloma »

[d] 1r3k1r/1bp5/1p1bR1Q1/3p4/3P4/2P5/P4PPP/6K1 w - - 0 1
Most engines find here only mate in 5 :shock:
35.Tf6+ Ke7 36.Tf7+ Kd8 37.Df6+ Ke8 38.De6+ Kd8 39.Dd7#

Only Houdini, Sparc, Zappa and Yace find correct mate in 3 !!

Analysis by Spark-1.0-win64-mp 1T:

35.Df5+ Kg8 36.Tg6+ Kh7 37.Dh5#
+- (#3) Tiefe: 7/5 00:00:00 5kN
35.Df5+ Kg8 36.Tg6+ Kh7 37.Dh5#
+- (#3) Tiefe: 8/5 00:00:00 6kN
35.Df5+ Kg8 36.Tg6+ Kh7 37.Dh5#
+- (#3) Tiefe: 9/5 00:00:00 7kN
35.Df5+ Kg8 36.Tg6+ Kh7 37.Dh5#
+- (#3) Tiefe: 120/5 00:00:00 124kN

This Position is from
17: Dirty - Spartacus, Int. CSVN Tournament 2013

Ok, Shredder 12 finds three mate too
Last edited by Paloma on Mon Jun 03, 2013 12:48 am, edited 1 time in total.
Top
Tennison
Posts: 183
Joined: Sat Nov 26, 2011 2:02 pm

Re: Why most engines can't find this mate in 3 ?

Post by Tennison »

I think you have problems with your engines ...


Critter, Toga, Stockfish, Crafty, Fritz, ... find this mate in 3 directly !

Even Fritz 5.32 find it ...
Top
User avatar
lucasart
Posts: 3232
Joined: Mon May 31, 2010 1:29 pm
Full name: lucasart

Re: Why most engines can't find this mate in 3 ?

Post by lucasart »

Yeah, I don't know what he's doing but any engine finds this instantly. My engine DiscoCheck finds it at depth 5 for example:

Code: Select all

info score cp 31995 depth 5 nodes 4670 time 2 pv g6f5 f8g7 e6g6 g7h7 f5f7
(a score of 31995 means mate in 5 plies, IOW side to move mates in 3 moves)
Theory and practice sometimes clash. And when that happens, theory loses. Every single time.
Top
Paloma
Posts: 1167
Joined: Thu Dec 25, 2008 9:07 pm
Full name: Herbert L

Re: Why most engines can't find this mate in 3 ?

Post by Paloma »

Analysis by Critter 1.6a 64-bit 1T:

35.Tf6+ Ke7 36.Tf7+ Kd8 37.Df6+ Ke8 38.De6+ Kd8 39.Dd7#
+- (#5) Tiefe: 27/21 00:00:01 4246kN

Analysis by Stockfish 3 JA 64bit 1T:

35.Tf6+ Ke7 36.Tf7+ Kd8 37.Df6+ Ke8 38.De6+ Kd8 39.Dd7#
+- (#5) Tiefe: 41/16 00:00:03 7273kN

Analysis by Crafty 23.2 JA x64:

35.Tf6+ Ke7 36.Tf7+ Kd8 37.Df6+ Ke8 38.De6+ Le7 39.Dxe7#
-+ (-#2758) Tiefe: 9 00:00:00 581kN

Analysis by Fritz 11:

35.Tf6+ Ke7 36.Tf7+ Kd8 37.Df6+ Ke8 38.De6+ Kd8 39.Dd7#
+- (#5) Tiefe: 8/15 00:00:00 16kN
Top
User avatar
Peter Skinner
Posts: 1763
Joined: Sun Feb 26, 2006 1:49 pm
Location: Edmonton, Alberta, Canada
Full name: Peter Skinner

Re: Why most engines can't find this mate in 3 ?

Post by Peter Skinner »

Crafty 21.1, 21.2, 21.3, 21.4, 21.5, 21.6

5 +327.62 427 0:00.00 1. Qf5+ Kg7 2. Rg6+ Kh7 3. Qf7#

Something is wrong with your engines of the interface you are using.

Peter
I was kicked out of Chapters because I moved all the Bibles to the fiction section.
Top
Paloma
Posts: 1167
Joined: Thu Dec 25, 2008 9:07 pm
Full name: Herbert L

Re: Why most engines can't find this mate in 3 ?

Post by Paloma »

Peter Skinner wrote: Something is wrong with your engines of the interface you are using.

Peter
No, the reason is i analysis this direct in the game notation, not from the FEN-string :)

to show how different Analysis between FEN-string an Notation can be.

This occurs more often than you think.
It is therefore important from which case analysis starts.

Load this game and start from 34... Kf8

[Event "Int. CSVN Tournament"]
[Site "Leiden"]
[Date "2013.06.02"]
[Round "5.1"]
[White "Dirty"]
[Black "Spartacus"]
[ECO "A40"]
[Result "1-0"]

1. d4 b6 2. e4 Bb7 3. Nd2 e6 4. Ngf3 Nf6 5. Bd3 d5 6. exd5
exd5 7. O-O Nc6 8. Ne5 Nxe5 9. Re1 Nfd7 10. Nf3 Bb4 11. Bg5
f6 12. Nxe5 Nxe5 13. Rxe5+ Kf7 14. Qf3 a5 15. c3 Bd6
16. Re3 a4 17. Rae1 a3 18. Re6 axb2 19. Rxf6+ Kg8 20. Qh5
Qxf6 21. Bxf6 gxf6 22. Qg4+ Kf8 23. Qe6 b1=Q 24. Qxf6+ Kg8
25. Bxb1 Rf8 26. Qg5+ Kf7 27. Qf5+ Kg7 28. Qg4+ Kf7 29. Re6
Rb8 30. Bg6+ hxg6 31. Qxg6+ Kf8 32. Qf5+ Kg7 33. Qf6+ Kg8
34. Qg6+ Kf8 35. Qf5+ Kg7 36. f4 Rh6 37. Qg5+ Kf7 38. Qxh6
Be7 39. Qg6+ Kf8 40. Qf5+ Bf6 41. Rxf6+ Ke7 42. Rf7+ Kd8
43. Qd7# 1-0
Top
User avatar
lucasart
Posts: 3232
Joined: Mon May 31, 2010 1:29 pm
Full name: lucasart

Re: Why most engines can't find this mate in 3 ?

Post by lucasart »

Paloma wrote:
Peter Skinner wrote: Something is wrong with your engines of the interface you are using.

Peter
No, the reason is i analysis this direct in the game notation, not from the FEN-string :)

to show how different Analysis between FEN-string an notation can be.

This occurs more often than you think
It is therefore important from which case analysis starts.

Load this game and start from 36... Rh6

[Event "Int. CSVN Tournament"]
[Site "Leiden"]
[Date "2013.06.02"]
[Round "5.1"]
[White "Dirty"]
[Black "Spartacus"]
[ECO "A40"]
[Result "1-0"]

1. d4 b6 2. e4 Bb7 3. Nd2 e6 4. Ngf3 Nf6 5. Bd3 d5 6. exd5
exd5 7. O-O Nc6 8. Ne5 Nxe5 9. Re1 Nfd7 10. Nf3 Bb4 11. Bg5
f6 12. Nxe5 Nxe5 13. Rxe5+ Kf7 14. Qf3 a5 15. c3 Bd6
16. Re3 a4 17. Rae1 a3 18. Re6 axb2 19. Rxf6+ Kg8 20. Qh5
Qxf6 21. Bxf6 gxf6 22. Qg4+ Kf8 23. Qe6 b1=Q 24. Qxf6+ Kg8
25. Bxb1 Rf8 26. Qg5+ Kf7 27. Qf5+ Kg7 28. Qg4+ Kf7 29. Re6
Rb8 30. Bg6+ hxg6 31. Qxg6+ Kf8 32. Qf5+ Kg7 33. Qf6+ Kg8
34. Qg6+ Kf8 35. Qf5+ Kg7 36. f4 Rh6 37. Qg5+ Kf7 38. Qxh6
Be7 39. Qg6+ Kf8 40. Qf5+ Bf6 41. Rxf6+ Ke7 42. Rf7+ Kd8
43. Qd7# 1-0
Obviously the past moves introduce a constraint not to go through a 3-fold repetition (some buggy engines use 2-fold). And the shortest mate *under this constraint* is a mate in 5. So everything is normal.
Theory and practice sometimes clash. And when that happens, theory loses. Every single time.
Top
Spliffjiffer
Posts: 416
Joined: Thu Aug 02, 2012 7:48 pm
Location: Germany

Re: And why most engines can't find this draw ?

Post by Spliffjiffer »

[d] 1R6/pPk1r3/2p5/K7/8/2B1b3/8/8 w - - 0 1

Ka6 draws, but almost no engine can find it...

But if you move Ka6 by yourself and let the engine think after this, they will find a draw-score nearly instantly !
Wahrheiten sind Illusionen von denen wir aber vergessen haben dass sie welche sind.
Top
kgburcham
Posts: 2016
Joined: Sun Feb 17, 2008 4:19 pm

Re: And why most engines can't find this draw ?

Post by kgburcham »

[D] 1R6/pPk1r3/2p5/K7/8/2B1b3/8/8 w - -

6 processor(s) found, POPCNT available
NUMA configuration with 1 node(s), offset 0
4096 MB Large Page Hash
Nalimov 6 men EGTB available - 999 MB cache
Engine: Houdini 3 Pro x64 (4096 MB)
by Robert Houdart
20/43 0:00 -0.96 1.Rg8 Kxb7 2.Rg4 Rf7 3.Rb4+ Bb6+ 4.Ka4 Rf3 5.Be5 Rd3 6.Rg4 Bc5 7.Bb2 Kb6 8.Rg8 Bd6 9.Rg6 a6 10.Re6 Bf8 11.Re8 Bc5 12.Re6 Rd2 13.Kb3 (17.447.050) 17748 TB:7
21/43 0:01 -1.05-- 1.Rg8 Kxb7 (27.078.311) 18210 TB:11
21/43 0:01 -0.89++ 1.Ka6 (33.394.079) 18308 TB:22
21/43 0:01 -0.73++ 1.Ka6 (33.450.278) 18298 TB:22
other best move - reduce depth to 18
18/43 0:01 -0.41++ 1.Ka6 (33.469.580) 18289 TB:22
18/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bg1 7.Bg3 Bc5 8.Bf4 Bf2 9.Be5 c5 (33.515.256) 18274 TB:22
19/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bg1 7.Bg3 Bc5 8.Bf4 Bd4 9.Bd6 c5 (33.551.081) 18254 TB:22
20/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bg1 7.Bg3 Bc5 8.Bf4 Bd4 9.Bd6 c5 (33.591.083) 18236 TB:22
21/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 c5 8.Bxc7+ Kxc7 9.Kxa7 c4+ 10.Ka8 (33.758.493) 18218 TB:22
22/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 c5 8.Bxc7+ Kxc7 9.Kxa7 c4+ 10.Ka8 (34.023.342) 18194 TB:25
23/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bf2 9.Be5 c5 (34.805.322) 18156 TB:29
24/43 0:01 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bf2 9.Be5 c5 (35.770.456) 18093 TB:41
25/43 0:02 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bf2 9.Be5 c5 10.Bxc7+ Kxc7 11.Kxa7 c4+ 12.Ka8 (37.333.323) 18061 TB:60
26/43 0:02 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bf4 Bg1 (39.296.365) 18042 TB:85
27/43 0:02 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bf4 Bg1 (42.460.025) 18029 TB:123
28/43 0:02 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 c5 10.Bxc7+ Kxc7 11.Kxa7 c4+ 12.Ka8 (47.343.135) 18042 TB:221
29/43 0:03 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (54.309.735) 18103 TB:362
30/43 0:03 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (63.423.758) 18183 TB:565
31/43 0:04 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (77.158.538) 18318 TB:964
32/44 0:05 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (96.622.287) 18456 TB:1.655
33/44 0:06 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (130.070.502) 18653 TB:3.147
34/47 0:09 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (173.348.633) 18980 TB:4.910
35/47 0:12 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (239.984.140) 19134 TB:8.902
35/47 0:13 0.00 1.Ka6 Kxb8 2.Be5+ Rc7 3.Bd6 Bd4 4.Bh2 Bf2 5.Be5 Bc5 6.Bf4 Bf2 7.Be5 Bc5 8.Bh2 Bd4 9.Bd6 Be3 (261.719.261) 19173 TB:10.778
Top
User avatar
Marek Soszynski
Posts: 581
Joined: Wed May 10, 2006 7:28 pm
Location: Birmingham, England

Re: And why most engines can't find this draw ?

Post by Marek Soszynski »

Spliffjiffer wrote:Ka6 draws, but almost no engine can find it...
On my system Critter finds it in well under a minute. But I gave up waiting for Crafty, Firenzina, Komodo CCT, Shredder, various versions/derivatives of Stockfish...
Marek Soszynski
Top

Return to “Computer Chess Club: General Topics”