From: Stephen J Lamb DEV ALS CO UK>
Date: 14 dec 1995
Subject: Re: IGS/ISS thread
> > 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 :) :).
Another significant difference that must be accounted for is the
range of possible grades. The weakest Shogi rank possible is, as far
as I know, 15 kyu and not 30(?) kyu as on the IGS server at the
moment. The strongest possible amateur grade is 6 dan (7 dan
anyone?).
> 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.
A common handicap system is as follows:
1 grade : Weakest player is Black.
2 grades : Left Lance.
3 grades : Bishop.
4 grades : Rook.
5 grades : Rook, Left Lance.
6 grades : Rook, Bishop.
7 grades : Rook, Bishop, Left Lance.
8 grades : 4 pieces (Rook, Bishop, Both Lances).
9 grades : 5 pieces (Rook, Bishop, Left Night, Both Lances).
10 grades+ : 6 pieces (Rook, Bishop, Both Nights, Both Lances).
I certainly agree that it would be more complicated to count handicap
games as ranking games. We've been using the Chess ELO system in
Europe for a number of years now to handle Shogi ranks, which seems to
be fairly successful. Handicap games are not used to update ELO ranks
since it was thought it would add too much complexity to the ranking
system.
> 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.
Not much... it's something like 53% wins for Black in pro games.
Don't know about amateur games though.
Steve Lamb.