computer-go: Ratings, God and everything.

["Mark Boon" <tesuji@xxxxxxxxx>]

Just a small contribution to a discussion that seems more emotional rather
than rational. I've done a little bit of analysis for ratings of players for
a general rating system. I used a simple notion that player A is one rank
higher than player B if he wins two out of three games. I also assume that
if player A is one rank higher than player B and player B is one rank higher
than player C, player A is two ranks higher than player C. (This is not a
trivial assumption, but the discussion gets too complicated otherwise.)

Based on some data that I found (which may be flawed data, I don't know) it
seems that in Chess one rank is equivalent to 80 ELO points. Using the same
scale, one stone handicap in Go seemed to end up being 155 ELO points. It's
worth a little less than two ranks. Note here that one stone handicap means
the game is played with black getting two stones handicap and white getting
5 komi. (See this as black putting down two stones as his first move instead
of one, but the conditions are the same as an even game otherwise.)

Next comes the problem of mapping. If one bluntly maps 1-dan to 2000 ELO
points (just an example) and then starts stating that therefore a 3-dan
player is equivalent to a 2310 ELO chess player it's a big mistake.
Consistently doing this will either end up having weak Go players with
negative ELO ratings, or by having a 9-dan professional having a 1000 points
more than Kasparov. Obviously one cannot compare this way. All this tells us
is that Go seems to have many more levels than Chess that would allow the
better player to win two out of three games. This may indicate that Go is
more complex than Chess.

As for the discussion about playing against a GoGod:
I've talked to professionals who estimated the difference between a top
player and perfect play is somewhere between 3 and 4 stones. Otake (9-dan)
once said that if his life depended on it to win, he would surely need 4
stones. But he admitted he might actually need 5 stones, but it would be
against his pride as a professional to take 5 stones and he would rather
die. Fact is of course that nobody knows, and that's the same for Chess.

As for the discussion about God:
We use these terms in a way that most here understood without any intention
of hurting anyone. We don't need to be censured by people who drop in and
see the word 'God' used in a way they're not used to. In my opinion this
group is trying to have scientific discussions and throughout history
christianity has been known to try to inhibit scientific advance. I hope
this will not be the case in this group.

    Mark