TalionThe answer to 1 would be to resign. White's upper left group is dead as it stands after black 1. white has lost the game, his best chance is probably to try and defend still while he hopes for black to make a mistake, a slim chance. Oh and since 1 won the game it is obviously the best move for black :)
twold: Winning the game is not a sufficient condition for a move to be considered best. It just means the move is "good enough" :-)
kb: may be the best move, but I don't think it's possible to kill White. Let's see what happens when White resists:
If , then in order to kill, B must play and follow through with ( threatens to make a second eye at ), but then after , Black has a big problem on his hands. If he plays at a, then White takes the ko, and then captures at (there are no ko threats large enough!). If he plays at b, then...
Black cannot atari at a due to damezumari.
Black cannot block at a due to damezumari.
twold: That is correct, but black can simply take two stones and atari at . Then if white resists with , snapback with at . So if I am not mistaken, you can delete the following discussion.
Later: ah now I see. There is a mistake in your previous diagram. I'll fix it.
This means Black really can't go for the kill, but he can live with his bottom left group in sente:
Assuming no prisoners prior to the initial diagram, Black has 4 prisoners to White's 2, and 11 points to White's 11. Without komi White would lose by 2 points.