Many Faces thinks X wins if X moves first (85%), but unclear if white moves first (51%) with no change after huge numbers of playouts. Good test position. I've seen from KGS games that Many Faces does not handle endgame kos very well. This is another example.
David > -----Original Message----- > From: [email protected] [mailto:computer-go- > [email protected]] On Behalf Of Brian Sheppard > Sent: Friday, August 14, 2009 9:46 AM > To: [email protected] > Subject: [computer-go] Interesting endgame case > > 1 2 3 4 5 6 7 8 9 > A - - O - - - - - - > B X X X O X - - - - > C O O X O X X - - - > D O - O X X - X X - > E - O O O X X O X X > F - X O - X O O O X > G - X O - X O O - O > H O X O - X X O O - > J - - - O X - X O - > O to play > > I analyzed this position as a loss for O, as follows: > > O has 22 points at left, and will gain 1 point from F4/G4/H4 > O has 13 points at right, with a Ko to potentially gain 2 > O has two ways to win: the Ko on J6/J7, or gain two of F4/G4/H4 > > Since H4 is sente for X, O should start with H4. This looks winning > for O because O will gain another point from F4/G4. Unfortunately, > X can win both F4 and G4 by using his doomed stones on F2. > Some variations: J2-J3-F1-E1-F4-G1-G4, and J2-F1-G1-E1-F4-J3-G4. > > If H4 does not win, then O must start his ko immediately with J6. > X has ko threats with H9, H4, E1 (or F1). O has Ko threats with > A4 and then A2 and H4 (which threatens to win by taking *two* of > the dame from F4/G4/H4. > > Since X has more ko threats, it seems like O should not win. > Extensive simulations supported this theory. > > But now I have a new version of Pebbles, and it says that O should win. > > What do you think? > > _______________________________________________ > computer-go mailing list > [email protected] > http://www.computer-go.org/mailman/listinfo/computer-go/ _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
