From: Albyn Jones <jones <at> REED <dot> EDU>
Date: 13 dec 1995
Subject: Re: IGS/ISS thread

Tim says:

>> From: Albyn Jones <jones <at> REED <dot> EDU>
>
>> there should be no significant differences in the rating algorithm.
>> one question is: what is the nominal difference between ranks?  in
>> go i believe that a one stone difference in rank is presumed to
>> correspond to a winning probability of 2/3 for the higher ranked player.
>> is the traditional ranking system in shogi based on the same assumption?
>
>Well, this is already a significant difference in the algorithm.  There
>is no idea about 'stones'.  (At least the last time I played Shogi :) :).
>

 :-)

>Yes, the basic presumption about the rating system is the basis for difference
>in rank.  One stone is the same as one rank, or there abouts.
>
>So for Shogi games, a handicap game should not be counted.  Because I do
>not know of any piece to rank difference off hand.  I imagine there is one,
>just I am not sure how simple it would be.  Also, in Go, the person who
>goes first gets a 0.5 advantage, where 1.0 == one stone.  None of this
>makes sense for Shogi.  Although, the person who does has the first move
>probably does have an advantage.
>

here's a suggestion, or two:
        1) ignore color until you have collected enough data (results of games
        between players of the same rank) to have a good idea of the effect.
        2) let the rating algorithm estimate the effect of color :-)
        3) ignore handicap games until you have collected enough data...
                or maybe permanently.

        in go, handicap games with more than a small number of stones
        are usually really teaching games, and thus not informative about
        player's relative strength.  therefore, they should be ignored.
        is there a similar tradition in shogi?

albyn