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Subject: Re: Hossa finds Qa7 with experimental blocked position code enabled

Author: Paul

Date: 07:38:44 02/05/01

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On February 05, 2001 at 02:27:12, Steffen Jakob wrote:

>On February 03, 2001 at 20:03:33, Eduard Nemeth wrote:
>
>>It is a simple testposition ( my new composition :), but i think it is for
>>chess-programs hard! :)
>>
>>[D]qrk5/1p2Kp2/pBp1pPb1/P1P1P3/8/8/8/8 b - - 0 1
>>
>>Black win!
>
>Very nice position!
>
>Normally Hossa has no chance to find the solution. Some time ago I worked on an
>idea to detect and evaluate such blocked positions. The main idea is to not only
>evaluate a position statically but also to consider how the evaluation
>progresses from ply to ply. If you already seem to have such a big advantage
>like black in Eduards test position than you "should" be able to make this
>advantage bigger within "some" plies. If you are not able to do this, then this
>is a strong indication for a blocked position. I have written a liitle bit about
>this on Hossa's homepage (http://www.jakob.at/steffen/hossa.html).
>
>I even have written some experimental code for this idea and it works partly. It
>has some very nasty side effects though, and therefore it's not part of the
>standard Hossa. But: if I activate this code then Hossa finds the solution Qa7
>after 16 seconds:
>
> depth   value    time    nodes pv
>    1   +15.82    0.02        3 1... g6e4 2.e7xf7
>  7/1   +17.33    0.03       15 1... g6h5
>   <1>  +17.33    0.03       17 1... g6h5
>    2   +17.49    0.03       27 1... g6h5 2.e7d6
>   <2>  +17.49    0.03       41 1... g6h5 2.e7d6
>    3   +17.70    0.03       85 1... g6h5 2.e7d6 h5f3
>   <3>  +17.70    0.03      189 1... g6h5 2.e7d6 h5f3
>?   4   +16.46    0.05      533 1... g6h5 2.b6c7 h5g6 3.c7xb8 c8xb8
>?  <4>  +16.46    0.06      691 1... g6h5 2.b6c7 h5g6 3.c7xb8 c8xb8
>    5   +16.45    0.07     1019 1... g6h5 2.b6c7 a8a7 3.c7xb8 a7xb8
>   <5>  +16.45    0.13     2349 1... g6h5 2.b6c7 a8a7 3.c7xb8 a7xb8
>  2/6   +16.16    0.16     3367 1... g6d3 2.e7e8 d3e4 3.e8xf7 c8d7
>                                4.f7g7
>   <6>  +16.16    0.20     4326 1... g6d3 2.e7e8 d3e4 3.e8xf7 c8d7
>                                4.f7g7
>!   7   +16.78    0.25     5893 1... g6d3 2.e7e8 d3e4 3.e8xf7 c8d7
>                                4.f7g7 b8g8 5.g7h6
>!  <7>  +16.78    0.36     9796 1... g6d3 2.e7e8 d3e4 3.e8xf7 c8d7
>                                4.f7g7 b8g8 5.g7h6
>?   8   +13.49    0.56    19307 1... g6d3 2.e7e8 d3e2 3.e8e7 e2h5
>                                4.b6c7 b6 5.c7d6 b6xa5 6.d6xb8
>?  <8>  +13.49    0.64    22453 1... g6d3 2.e7e8 d3e2 3.e8e7 e2h5
>                                4.b6c7 b6 5.c7d6 b6xa5 6.d6xb8
>!   9   +13.58    0.73    27196 1... g6d3 2.e7e8 d3e2 3.e8e7 e2d1
>                                4.e7d6 d1c2 5.b6c7 b6 6.c7xb8 b6xa5
>!  <9>  +13.58    0.89    34857 1... g6d3 2.e7e8 d3e2 3.e8e7 e2d1
>                                4.e7d6 d1c2 5.b6c7 b6 6.c7xb8 b6xa5
>?  10    +6.92    1.45    66720 1... g6d3 2.e7e8 d3c2 3.e8e7 c2e4
>                                4.e7e8 a8a7 5.b6xa7 b8a8 6.a7b6
>? <10>   +6.92    1.69    82593 1... g6d3 2.e7e8 d3c2 3.e8e7 c2e4
>                                4.e7e8 a8a7 5.b6xa7 b8a8 6.a7b6
>!  11    +6.90    1.98   100809 1... g6d3 2.e7e8 d3f1 3.e8e7 f1e2
>                                4.e7e8 e2d3
>! <11>   +6.90    2.71   146194 1... g6d3 2.e7e8 d3f1 3.e8e7 f1e2
>                                4.e7e8 e2d3
>!  12    +6.90    3.27   186272 1... g6d3 2.e7e8 d3f1 3.e8e7 f1e2
>                                4.e7e8 e2d3 5.e8e7 d3e4
>! <12>   +6.90    4.40   265299 1... g6d3 2.e7e8 d3f1 3.e8e7 f1e2
>                                4.e7e8 e2d3 5.e8e7 d3e4
>!  13    +6.90    5.58   348430 1... g6d3 2.e7e8 d3e2 3.e8e7 e2f1
>                                4.e7e8 f1c4 5.e8e7 c4e2
>!2/13    +7.38   15.98   998322 1... a8a7 2.b6xa7 b5 3.c5xb6 c5
>                                4.e7d6 c4 5.b7 c8xb7 6.a7d4 b8d8
>                                7.d6c5 g6d3 8.d4c3 d8d5 9.c5b4
>! <13>   +7.38   16.36  1023359 1... a8a7 2.b6xa7 b5 3.c5xb6 c5
>                                4.e7d6 c4 5.b7 c8xb7 6.a7d4 b8d8
>                                7.d6c5 g6d3 8.d4c3 d8d5 9.c5b4
>
>Best wishes,
>Steffen.

Hi!

I've been thinking along the same lines yesterday when I saw this problem,
but haven't implemented anything yet. It's great to see you've managed to get
this working! Congratulations!!

Now I'm going to be mean :) Does it also work on these positions? At least now
you have some more test positions ;)

[D]4k3/8/1p1p4/pPpPp1p1/P1P1PpPp/5P1P/2BB4/K7 w - - id White Wins; bm Bxf4
[D]5rk1/5p2/pr2pPp1/Pp1pP1Pp/1PpP3P/K1P5/8/8 w - - id Draw; am axb6
[D]8/8/8/1k3p2/p1p1pPp1/PpPpP1Pp/1P1P3P/QNK2NRR w - - id WW; bm Kd1
[D]3k2r1/5b2/2p5/rpPp1p1p/pP1PpPpP/P3P1P1/3K4/8 w - - id Draw; am bxa5
[D]8/3k3p/5p2/p1p1pPpP/PpPpP1P1/RP1P4/8/5K1R w - - id WW; bm h6

Best wishes,
Paul



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