Single Comment

Mating potential and piece values[Subject Thread] [Add Response]

H. G. Muller wrote on Thu, Sep 27, 2012 09:06 AM UTC:

> The increased knowledge of mating potential has raised the apparent value
of Commoner, then?

It seems so. To be frank, I am not entirely sure if the previous value
determination was for 8x8 or 10x8 board. I did a lot of 10x8 measurements
for Great Shatranj, where Commoner is one of the pieces. I also remember
having done some tests with divergent K+N combinations, though, and that
was most certainly on 8x8. But I remember I also found then that 3 of the 4
combinations were equal, and only mNcK was 50cP stronger. [Edit] I looked it up, and the conclusion then was that Commoner was 30cP weaker than Knight. So in that case good handling of the mating potential does seem to have a significant effect. Perhaps I should redo these tests with various aspects of the new knowledge disabled, to see what helps most. [End Edit]

The Knights vs Commoners match is now at 777 games, and the lead of the
Commoners has dropped to 6 points. Which is an excess of only 0.4%. Against
a standard deviation of 1.4%, so totally insignificant.

After 338 games the B-pair vs Commoners is at 57.4%. The excess of 7.4%
(+/- 2.2%) is exactly half of the 15% Pawn-odds score I remember from the
previous version of Fairy-Max. This also points to exact equality of Knight
and Commoner, as B-pair is also worth 50cP more than Knights. (Kaufman
values, confirmed by my tests with the old version. Which in this case
should not matter much, as neither B nor N have mating potential, and
drawing tricks based on KNNK are excedingly rare (plus that Fairy-Max is
not likely to be able to win KBNK either, not knowing in which corner to
drive the bare King)).

Next I will probably do B-pair vs Commoners + Pawn, to check if the sore
eactly reverses. (Doing an implicit determination of the effect of Pawn
odds at the same time as more Bishops vs Commoners comparison.)