Bulky Ten In The Corner
Black can play at any of the 7 marked intersections to live outright with 9 points of territory, but is best because it leaves either no ko threats or only one tiny one (depending on the rules). White-to-move plays .
is at k or s. (Note that White has already taken gote.)
Reminder: Although _the indicated sequence_ is sente, White took gote to get to the start of this diagram.
If White ignores Black's ko threat, then White plays at , which kills Black. If is still empty then after Black retakes the ko, Black's followup is capturing to live with 9 points under territory scoring. If White retakes the ko, then Black can back down from it with . (If Black would do that without having played a ko threat, then Black should not play this line.)
After Black backs down, the ko's swing becomes 9 points under territory scoring. White wins it with for a seki in which White captured 1 net Black stone. After , Black wins it by playing either of the other 2 marked points.