After , can make ko. threatens a snapback.
The difference between winning and losing this ko is 19 points of territory. If Black wins he gets only 4 points of territory, while if White wins she gets 15 points.
If here, then lives as per rectangular six. Subsequently, a and b are miai for life.
The difference between winning and losing this ko is 20 points, since Black gets 5 points if he wins it. gives up a possible point for nothing.
White wins the ko in an unusual way with . Now if Black takes the ko, White captures the stones. It would be a mistake for White to fill the ko, because that just leads to another ko.
is gote, gaining 0.5 point more than the ko. You can see that because if Black wins the ko he gets only 4 points, but if he plays first, he gets 5 points.