how do I know if my result is right? and how many moves are we talking about? --Tomas

Isn't this scenario a bit unlikey? How did black get to place two pieces in a row?

Black to play first at 1 is clear to stop white making two eyes. Then whatever happens next black just surrounds white. There is no way for white to escape. Next either white plays or black. In anycase black at the crucial point kills white.