[Retros] recent improvements

Mario Richter mri_two at t-online.de
Sun Dec 17 15:07:58 EST 2006


Andrew wrote:

> But really they belong to Mario, if you would care to peer into your

> database and tell us what the solutions are!

My goal with providing the list without giving example games/positions
was twofold:

- helping to avoid waste of time for attempts to improve
records which are already optimal

- giving those who try to improve the current records some indications
where their efforts can be succesful

So if somebody finds an instance for a category mentioned in my
list - like Olli and Noam recently did - then he should get the
attribution as the composer, not my computer.

> Extrapolating the values you gave, the 12 ply case might take of the order

> of 100 hours. Is this possible for you to run? Or does Francois Labelle


> access to more powerful hardware that he might run?

The way my program works, it isn't only a matter of time,
but of space too, so an exthausive search for plies > 11 might not
be the best solution or even impractical.

But I can pick out some of the current records which look like
they can be improved, and try to break them.

Noam wrote:

> Mario -- you didn't specify whether "realizable" means in a sound

> proof game or in an unrestricted game, but now I see it must have been

> the former because g7-g8Q(R)# can be easily shown in 11 ply without

> the soundness condition, e.g. 1 g4 g6 2 g6 Nh6 3 gxh6 Bg7 4 hxg7 h5

> 5 random Rh7 6 g8R#.

With realizable I meant exactly that:
- the proofgame has exactly one solution
- there is not shorter uniquely realizable game with
the same mating pattern (i.e. with e.g Pe7xd8# there is neither
a shorter correct SPG with Pe7xd8# nor one with Pe2xd1#).

> Did you keep track of how many sound proof games

> each minimally "realizable" promotion mate had?

For 9 and 10 plies I can provide them immediatly, the data for 11 plies
follow in a later posting:

9 plies:
125 Pb7xc8=R
8 Pc7xd8=R
16 Pg7xf8=R
24 Pc7-c8=Q
251 Pb7xc8=Q
42 Pc7xd8=Q
42 Pg7xf8=Q

10 plies:
6 Pg2xh1=R
54 Pd2-d1=Q
20 Pf2-f1=Q
11 Pf2xe1=Q
6 Pg2xh1=Q



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