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Subject: Re: Junior5 blind? Questioon for Uri

Author: Robert Hyatt

Date: 20:02:51 10/06/99

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On October 06, 1999 at 19:55:00, John Stanback wrote:

>On October 06, 1999 at 00:58:15, Robert Hyatt wrote:
>
>>On October 05, 1999 at 15:15:01, John Stanback wrote:
>>
>>>On October 05, 1999 at 01:14:03, Harald Faber wrote:
>>>
>>>>I remember I have heard that Junior has problems with "winning" pawns on a2/a7
>>>>and h2/h7. I couldn't imagine. Now I have seen it with my own eyes:
>>>>
>>>>[Event "Chessnet"]
>>>>[Site "?"]
>>>>[Date "????.??.??"]
>>>>[Round "?"]
>>>>[White "King 2.55"]
>>>>[Black "Junior 5"]
>>>>[Result "*"]
>>>>[ECO "D49"]
>>>>[PlyCount "43"]
>>>>
>>>>1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Bd3 dxc4 7. Bxc4 b5 8. Bd3
>>>>a6 9. e4 c5 10. e5 cxd4 11. Nxb5 Nxe5 12. Nxe5 axb5 13. Qf3 Bb4+ 14. Ke2 Rb8
>>>>15. Nc6 Bb7 16. Bf4 Qd7 17. Bxb5 O-O 18. Bxb8 Rxb8 19. Rhc1 Bd6 20. Kf1 Bxc6
>>>>21. Bxc6 Qa7 22. Rc2 *
>>>>
>>>>Now Junior5 takes the Ph2 and only is down with -1.00. After 23.g3 h5 (-1.32)
>>>>24.Kg2 Ng4 (-1.40) 25.Rd1 Rf8 (-1.55)
>>>>
>>>>Black has some problems getting the bishop back into the game...
>>>>
>>>>So Uri, what does your latest Junior version (5.9?) play, also take the pawn?
>>>>
>>>>And I wonder which other programs take this pawn and which avoid this trap?
>>>
>>>Zarkov takes about 10 milliseconds to switch from Bxh2 to Rc8 :).
>>>
>>>John
>>
>>
>>Crafty _never_ considers Bxh2:
>>
>>         nss  depth   time  score   variation (1)
>>                1     0.00  -2.19   22. ... Qc7
>>                1->   0.00  -2.19   22. ... Qc7
>>                2     0.00  -2.32   22. ... Qc7 23. Qd3
>>                2     0.01  -2.31   22. ... Qa6+ 23. Kg1 d3
>>                2->   0.01  -2.31   22. ... Qa6+ 23. Kg1 d3
>>                3     0.02  -2.48   22. ... Qa6+ 23. Kg1 Qc8 24. Qd3
>>                3     0.03  -2.31   22. ... Qc7 23. Qd3 Bb4
>>                3     0.03  -2.30   22. ... Qe7 23. Qd3 Be5
>>                3->   0.03  -2.30   22. ... Qe7 23. Qd3 Be5
>>                4     0.04  -2.39   22. ... Qe7 23. Qd3 Be5 24. Kg1
>>                4     0.06  -2.35   22. ... Qc7 23. Qd3 Rb6 24. Bd5
>>                4->   0.08  -2.35   22. ... Qc7 23. Qd3 Rb6 24. Bd5
>>                5     0.12  -2.33   22. ... Qc7 23. Qd3 Be5 24. Bd5 Qd6
>>
>>
>>It has an eval term to stop that nonsense.  Many programs don't, still.
>
>The reason that Zarkov takes a 2 ply search is that my evaluation
>term doesn't kick in until after the pawn moves to g3 trapping
>the bishop.
>
>John

aha...  I check for the presence of the pawn on g3, and make sure (using SEE)
that it isn't en prise.  Then I zap the score...  probably just as good to let
the pawn get there first and save some time...



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