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Subject: Re: Can this position be won under a 50-move rule?

Author: guy haworth

Date: 12:43:06 09/17/00

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Thanks for your reply.

Certainly, endgame tables (EGTs) specific to the 50-move rule can be computed by
recomputing the Distance-to-Conversion tables, marking everything deeper than
100 plies as a draw.

The objection to this is

  (a) FIDE could change '50' to '45' (unlikely), and

  (b) it is still worth knowing that there a win in 51:  the opponent might be
fallible.


Instead, I proposed, in the ICGA_Journal, a new metric called 'DTR' or "Depth by
The Rule".  If a position can be won under a k-move rule but not under a
k-1-move rule, it has DTR = k.

The DTR tables are not as easy to compute as the DTC and DTM ones but they can
be done.

At the same time, I conjectured that positions might be found in KQP(a5-6)KQ and
KBBKNN which would demonstrate the need for a DTR table.  It may be that the
maxDTC/DTM position is one such.

It has DTC = 38 and DTM = 106 ... which is not to say that the KBBKN phase is
bound to be 68 moves deep.

However, it is clear that White cannot just aim to minimise DTM.  White has to
'invest' more effort in Phase 1 to reach a shorter Phase 2.  As White has only
12 spare moves for this, there may not be enough spare time.

Should the maxDTC/DTM KBBKNN position not be a '50-win', there are probably
KBBKNN positions en route which can be won with DTR but not with DTC/DTM alone.

Why 'Marimer' by the way? :-)

G



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