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Subject: Re: Two mate positions to solve.

Author: Bert van den Akker

Date: 08:32:09 09/03/00

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On September 02, 2000 at 17:08:20, leonid wrote:

>Hello!
>
>Please solve these two positions and say minimum number of moves that lead to
>it.
>
> 1r2k2r/1b3pbp/1NPqN1n1/1P1Q4/1P2P3/P3B3/5PP1/R3KB1R White to go.
>
> 6KQ/3B2Q1/QQQQQQQ1/5Nbn/qqqqq1q1/5qqk/8/8 White to go.
>
>It will be good if you will indicate all main parameters of your trial. At
>least, I see them this way:
>
>Name of your program. Hash table size.
>In what way (if you know) position was solved. Selective search or brute force
>search.
>Time for each way of search.
>CPU and its speed.
>
>If you could come with some of your "crazy" (fantasy) position or normal one, it
>will be good. When you will depose your, try to make them between 5 and 9 moves
>mate. That deep you still can expect reasonable time to be solved by brute force
>on our computers.
>
>Thanks in advance,
>Leonid.


Hello Leonid,

My program is basicly brute force but the extensions and null moves makes it
also selective.
Depending on the positions mates till 45 plies can be
solved in seconds. In this cases there are many checks and ony one reply on that
checks.

Here are my the results of the second positions:
[D] 6KQ/3B2Q1/QQQQQQQ1/5Nbn/qqqqq1q1/5qqk/8/8 w

Name program: Bobo
Hash table size: 262144 entries
recursiv null move on

extensions used:
Check extension
Threat extension
Single move out of check extension in normal search

Single move out of check extension in quiet search


Nf5xg3
(score= 1941) (depth= 1/1)
(time = 19.9900000000052)
(evaluations= 401986)
Nf5xd4
(score= 1942) (depth= 1/1)
(time = 26.5300000000061)
(evaluations= 530496)
Nf5xd4
(score= 1943) (depth= 1/1)
(time = 32.0200000000041)
(evaluations= 637640)
Qa6xa4
(score= 1944) (depth= 1/1)
(time = 40.2100000000064)
(evaluations= 798971)
Qa6xa4  Qb4xd6  Qa4xc4  Qd4xc4  Qc6xe4  Qd6xb6  Qe6xc4  Qf3xe4  Qc4xe4  Qg4xe4
Qf6xb6
(score= 1954) (depth= 1/11)
(time = 60.0300000000061)
(evaluations= 1191561)
Qa6xc4
(score= 1955) (depth= 1/1)
(time = 65.2000000000044)
(evaluations= 1291614)
Qa6xc4  Qb4xd6  Qc6xd6  Qd4xd6
(score= 1963) (depth= 1/4)
(time = 76.9500000000044)
(evaluations= 1523217)
Qc6xc4
(score= 1964) (depth= 1/1)
(time = 93.4300000000003)
(evaluations= 1846206)
Qc6xc4  Qd4xQ6  Qc4xe4  Qd6xe6+ Ld7xe6
(score= 1965) (depth= 1/5)
(time = 102.330000000002)
(evaluations= 2013926)
Qc6xe4
(score= 1966) (depth= 1/1)
(time = 108.090000000004)
(evaluations= 2122987)
Qc6xe4  Qd4xQ6  Pf5xd6  Qc4xe6+ Ld7xe6
(score= 1967) (depth= 1/5)
(time = 118.040000000001)
(evaluations= 2302593)
Qc6xe4  Qd4xe4  Pf5xg3  Qe4xg6  Qf6xg6  Qg4xe6+ Ld7xe6+ Kh3-g2
(score= 1946) (depth= 2/8)
(time = 102.709999999999)
(evaluations= 2114069)
Qg6xh5+
(score= 1947) (depth= 2/1)
(time = 123.139999999999)
(evaluations= 2482105)
Qg6xh5+ Qg4xh5  Qh8xh5+ Kh3-g2  Qc6xe4  Qd4xe4  Qd6xg3+ Qf3xg3  Pf5xg3
(score= 2309) (depth= 2/9)
(time = 281.709999999999)
(evaluations= 5391421)
Qg6xh5+
(score= 2537) (depth= 3/1)
(time = 25.3699999999953)
(evaluations= 513635)
Qg6xh5+ Qg4xh5  Qh8xh5+ Qg3-h4  Pf5xh4+ Qc4xe6+ Bd7xe6+ Qe4xe6+ Qd6xe6+ Qf3-g4
Qe6xg4+ Qd4xg4  Qh5xg4+ Kh3xg4  Qb6xb4+ Kg4-g3  Qf6xg5+ Kg3-h2  Qa6-e2+ Kh2-h3
Qe2-f3+ Kh3-h2  Qf3-f4+ Kh2-h3  Qf4-f5+ Kh3-h2  Ph4-f3+ Kh2-h1  Qf5-h7+
(score= 19971) (depth= 3/29)
(time = 135.769999999997)

Mate in 15 moves




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