TsumegoFromGames134/Solution

Black plays first  

secures his territory. Later - are an ambiguous exchange. Black gets 9 points of territory.

White plays first  

fills at .

puts the four stones in atari. Later - are sente. Black gets 3 points and White gets 8 points, for a net local score of -5. The original position has a count of +2, and a play gains 7 points.

Two stage throw-in ko  

If connects his stones, White can make a two stage throw in ko. Black may choose this option if he is komaster.

Ko avoidance  

If White starts with , may reply without ko. Then Black cannot connect after .

Ko threat  

Black can still play for ko with , but then White can use a as a ko threat, or play there to capture if Black plays at b without making ko.