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Subject: Agreed ...

Author: GuyHaworth

Date: 01:07:23 02/10/06

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I agree, which is why I say that Black's attempt at the swindle c8=Q?? is only
_arguably_ the best defence.

After c8=Q, White still needs 17 moves to capture the Rook or mate, so it's not
that easy.

[D] 2Q5/8/8/8/1K1r4/8/1k6/8 w

With strategies SC- v SC+ (minimaxing DTC) we have:

1.Kb5' Kb3 (Rd3) 2.Qc5' Rd8' 3.Qc4+' Kb2' 4.Qe4 (Qe6) Kc3' 5.Qe5+ (Qc6+) Kb3'
6.Qe6+' Kc2' 7.Kc4' Rd2' 8.Qe1' Rd8' 9.Qe4+' Kc1' 10.Qf4+ (Qf5) Kd1'
11.Qg4+' Kc2' 12.Qf5+' Kd1' 13.Kc3' Ke2 (Ke1) 14.Qe5+ (Qe6+) Kd1'
15.Qh5+' Ke1' 16.Qh4+' K~' 17.Qxd8' ...

calling for a lot of unique moves (indicated by ').

The Reference Fallible Player R(c) that I've defined and written about with
Rafael Andrist's help would take 17 moves as White if c = +infinity.  It would
take longer the less c was, and certainly - at some point - would be expected to
take more than 50 moves.  With c=0 for example, R(c)'s moves would be as likely
to be one (winning) move as another which can be easily simulated by hand.

You may feel that White's moves are harder to find than Black's:  it's not clear
to me.  A Monte Carlo run of R(c)-R(c) games for various 'c' would show whether
expected-game-length would be more or less than 17.

Walter Browne's 'equivalent R(c)' was about R(19) when he played a couple of
KQKR endgames against Thompson's BELLE.

g



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