Author: Terry McCracken
Date: 14:36:33 04/08/02
Go up one level in this thread
On April 08, 2002 at 14:31:20, Martin Giepmans wrote:
>On April 08, 2002 at 10:49:00, Terry McCracken wrote:
>
>>On April 08, 2002 at 09:45:43, Martin Giepmans wrote:
>>
>>>On April 07, 2002 at 15:48:22, Terry McCracken wrote:
>>>
>>>>Here's an Endgame that should make _all_ chess engines really work!
>>>>
>>>>Fritz 7 sees the draw but doesn't understand the loss after 1.Qe8+..Qf8??
>>>>
>>>>Played by Mieses-NN 1903. Mieses won after Qf8??, I'll give the main line.
>>>>
>>>>
>>>>1.Qe8+ Qf8 2.h5 Nf7 3.Kc2 Nd8 4.Kc3 Nf7 5.a4 Nd8 6.Kc4 Nf7 7.Kd5 Nd8 8.b4 Nf7
>>>>9.Kc6 Nd8+ 10.Kc7 Line
>>>>
>>>>After Qe8+..Kh7! is correct. After 2.Qxd8...Qd2 will draw with perpetual check.
>>>>
>>>>[D]3n2k1/p2P2p1/1p6/7Q/5q1P/8/PP6/1K6 w - -
>>>>
>>>>Terry
>>>
>>>I get this:
>>>
>>>SpiderChess (amd 1200)
>>>05 00:00:00 + 0.77 H5-E8 F4-F8 B1-C2 G7-G6 E8xF8 G8xF8
>>>06 00:00:00 + 0.33 H5-E8 F4-F8 B1-C2 G7-G6 E8xG6 G8-H8 C2-D3
>>>07 00:00:00 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3
>>> D5xA2
>>>08 00:00:00 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3
>>> D5-E5 C3-B4 E5xB2 B4-C4
>>>09 00:00:02 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3
>>> D5-E5 C3-D3 E5-F5 D3-C4
>>>10 00:00:11 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3
>>> D5-E5 C3-D3 E5-F5 D3-C4 F5-F7 C4-B5
>>>
>>>(score +0.10 means that the engine thinks that it is probably a perpetual)
>>>
>>>After Qe8 Qf8 the score rises immediately:
>>>05 00:00:00 + 0.75 B1-C2 D8-F7 C2-D3 G7-G5 E8xF8 G8xF8
>>>06 00:00:00 + 0.79 B1-C2 D8-B7 C2-D3 G7-G5 E8xF8 G8xF8
>>>07 00:00:00 + 0.61 B1-C2 G7-G5 E8-G6 G8-H8 G6-H5 H8-G7 H5xG5 G7-H7 C2-D3
>>>08 00:00:00 + 0.65 B1-C2 G7-G5 H4xG5 G8-G7 E8xF8 G7xF8 G5-G6 F8-G7 C2-D3
>>> G7xG6
>>>09 00:00:01 + 0.45 B1-C2 G7-G6 E8xG6 G8-H8 G6-E8 H8-G7 E8-E5 G7-G8 E5-G5
>>> G8-H7 C2-C3 F8-F3 C3-B4 D8-C6 B4-B5
>>>10 00:00:05 + 0.55 B1-C2 G7-G6 E8xG6 G8-H8 G6-E8 H8-G7 E8xF8 G7xF8 H4-H5
>>> F8-E7 H5-H6 D8-F7 D7-D8D F7xD8 H6-H7
>>>11 00:00:11 + 0.70 B1-C2 D8-F7 H4-H5 B6-B5 C2-D3 B5-B4 D3-D4 B4-B3 A2xB3
>>> G7-G5
>>>12 00:00:48 + 0.86 B1-C2 B6-B5 H4-H5 A7-A6 C2-D3 A6-A5 D3-E4 A5-A4 B2-B3
>>> A4xB3 A2xB3 G7-G5
>>>13 00:01:44 + 0.88 B1-C2 A7-A5 H4-H5 A5-A4 C2-D3 B6-B5 D3-E4 D8-F7 E4-D4
>>> A4-A3 B2xA3 G7-G5
>>>
>>>Apparently this is mainly eval, allthough the last pv begins to look right ;)
>>>
>>>Cheers,
>>>Martin
>>
>>
>>I'm surprised SpiderChess considers 1..Kh7! It is the _only_ move that survives,
>>and it does indeed looks like it wants to draw with perpetual!
>>
>>It may be the only engine that does!
>>
>>1..Qd2 also ensures perpetual and draws faster I believe.
>>
>>When you feed it 1..Qf8?, it still has problems seeing the loss, but does see
>>White is better, which is more than I can say for the top commercial programmes.
>>
>>But it doesn't play 2.h5! straight away and I think that White can't win if it
>>isn't played immeadiatly after 1..Qf8?
>>
>>1.Qe8+..Qf8? 2.Kc2?..g6! and it appears to be a draw with Qxg6+..kh7= with
>>another perpetual. However I haven't dug real deep here.
>>
>>I think you miss the win with White and let Black go. 1.Qe8+..Qf8? 2.h5! ++/-
>>and White will win.
>>
>>Still your eval is very good for finding perpetuals:o)
>>
>>Let SpiderChess work much longer and see if it changes 2.Kc2? to 2.h5! sealing
>>Black's fate.
>>
>>Terry
>
>The default ("positional") version of SpiderChess still wants to play Kc2 after
>10 minutes.
>With the tactical version I get:
>
>(position after Qe8 Qf8):
>.........
>10 00:00:19 + 0.55 B1-C2 G7-G6 E8xG6 G8-H8 G6-E8 H8-G7 E8xF8 G7xF8 H4-H5
> F8-E7 H5-H6 D8-F7 D7-D8D F7xD8 H6-H7
> 00:00:25 + 0.70 H4-H5 D8-F7 B1-C2 B6-B5 C2-D3 B5-B4 D3-D4 B4-B3 A2xB3
> G7-G5 E8xF8 G8xF8
>11 00:00:39 + 1.21 H4-H5 D8-F7 B1-C2 B6-B5 C2-D3 B5-B4 D3-D4 B4-B3 A2xB3
> A7-A5 E8xF8 G8xF8
>11 00:00:43 + 1.21 H4-H5 D8-F7 B1-C2 B6-B5 C2-D3 B5-B4 D3-D4 B4-B3 A2xB3
> A7-A5 E8xF8 G8xF8
>12 00:01:06 + 1.16 H4-H5 D8-F7 B1-C2 B6-B5 C2-D3 B5-B4 D3-D4 A7-A5 D4-D5
> F7-D8 B2-B3 G7-G5 E8xF8 G8xF8
>
>It still doesn't see the whole line, I think, but it would probably play
>the right moves in a game with longer timecontrol.
>If this happens more often (I think you are right about Kc2 (?), it is a
>draw) the tactical version will become the default version ;)
>
>Cheers
>Martin
Well I'm impressed the engine is basically on the right track, it needs some
refinements; IE 1.h5!..Nf7 2.Kc2..b5 3.b4! is better than Kd3!? but not bad.
3.Kd3!?..b4 4.Kd4..a5 5.Kd5..Nd8 6.b3..g5? is a mistake, 7.h6! winning fast,
the threat is h7+! and 7.Qxf8?! another inaccuracy as 7.h6! and Black can
resign.
Other than some odd play your engine is working mostly on the right idea, with
more improvements it will be a killer in the endgame!;)
Best of Luck,
Terry
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