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Subject: Re: Tricky composed mate in 4

Author: Heiner Marxen

Date: 05:35:34 03/23/04

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On March 22, 2004 at 21:29:41, Thomas McBurney wrote:

>On March 21, 2004 at 12:14:16, William Kerr wrote:
>
>>[D]3R1B1K/5p2/2p2p2/b1rPNP1n/q1rkNP2/1Pp2Q1p/1n6/5B2 w - - bm Re8;id mate in 4,
>>Re8, Qxb3, Nxc5, Rxc5, Nxc6+, Rxc6, Qe4++;
>>
>>Tricky mate in 4 for dedicated machines and for some Null movers.
>>
>>Problem composed by L. Zagoruiko in 1972.
>
>
>Interesting, my chess program Kanguruh found a completely different line.  It
>took 6.5 seconds on a Athlon 650.
>
>2    522      61       15651  b3a4 ??
>2    537      64       17197  b3a4
>2    553      65       18016  f8c5 !!
>2    537      65       18347  f8c5 c4c5 b3a4
>3    573      66       19487  f8c5 c4c5 e5c6 a4c6 d5c6 a5d8
>3    576      76       28888  e4c5 !!
>3    573      79       31623  e4c5 c4c5 b3a4
>4    603      89       40914  e4c5 c4c5 b3a4 f6e5
>5    633     155      124428  e4c5 !!
>5    689     188      151551  e4c5 c4c5 f8c5 d4c5 e5d7 c5d6 d7b6 d6c7
>5    693     472      587619  e5g4 !!
>5    689     489      603651  e5g4 a5d8 f3e3 d4d5 e4f6 d8f6 g4f6 h5f6 e3e5 d5e5
>6  31990     643      895005  e5g4 a5d8 f3e3 d4d5 e4f6 d8f6 g4f6 h5f6 e3e5 d5e5
>0 0 0 0 Mate in  4

The PV for a mate in 4 cannot be longer than 7 plies.
Your line is 10 plies long, hence cannot be the PV for a mate in 4, right?

Cheers,
Heiner



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