[computer-go] Re: Should 9x9 komi be 8.0 ?]

[Weston Markham]

On 3/3/08, Christoph Birk <birk at ociw.edu> wrote:
>  If there are two lines of play from the viewpoint of the MC program:
>   a) leads to a 0.5 pt loss
>   b) may win if the opponent makes a stupid (!) mistake, but otherwise
>      leads to a bigger loss.
>
>  It is generally better to play for the 0.5 point loss as the oppoenent
>  may make a end-game mistake and loses 1 point.
>  But naive MC programs typically go for (b) which will lead to a
>  devastating loss because the opponent usually does not make the 10 point
>  mistake, but may have made the 1 point mistake.

I'm not sure if I understand what scenario you are trying to describe.
 It sounds to me as if you are supposing that the "MC program" is 100%
confident (or has reached some state that effectively amounts to this)
that the opponent will correctly defend its win in both cases, even
though in both cases there is an opportunity for the opponent to make
a mistake.  The only difference appears to be that (b) leads to a much
greater loss by the program.  (You also characterize the opponent's
blunder in (b) as "stupid", but I understand this to simply be a
subjective characterization based on the fact that it leads to a large
loss.)  In this case, if the program does not distinguish between
losses by differing numbers of stones, then it has no reason to favor
one move over the other.  (Perhaps it should resign rather than play
out either of these already-known-to-be-lost positions.)  At any rate,
this is not the same as saying that the program will "typically go for
(b)".  But is my understanding of your claim accurate?

So the situation you describe is something like:  (upper end of a 9x9
board, black (X) to play)
+---------+
|.X.XaXXX.|
|XXXXOOOXX|
|    O.OOb|
|     O.OX|
|       OO|

X has secure stones in the upper-left.  The group in the upper-right
can be connected at (a).  The X in the lower-right could connect at
(b), but it is sure to die as long as white responds at (a).  The rest
of the board is such that black will lose by 0.5 anyway if he plays
the "normal" move at a, and white responds with (b).  Do MC-based
programs really favor (b) over (a)?  (I am skeptical.)  Or is the
issue that Christoph and others believe that players should (for
whatever reason) favor (a)?

Weston