Hane connect exercise 1
Black and White have weaknesses at b and a respectively, as described on the hane tsugi/discussion page. Can White play the hane at ? What will be the outcome? Are there other options here ?
My analysis:
For Black to play the ko in this diagram looks dangerous, as his whole territory will be gone if he loses the ko. Still, if Black is komaster there might be an opportunity here.
Probably Black has to give way at . If White continues here, it should be at a; however, there is a good chance that White will play tenuki now, satisfied to have avoided the black hane at b in sente. My impression is therefoer that is a rather small move, but double sente. - Andre Engels
Bill: With the usual assumptions of yose, I get to be a 6 point sente. If Black b, Black a is worth only 4 points (miai).
If , White will probably not answer. After , White can play at or a. Note however that is simply a ko threat: it does not make any points (in theory White could make an approach ko for one point by playing at b, but in practice this is too risky). - Andre Engels
Bill: After the temperature has dropped to 0 (unless White is komaster). If then White a. Or - , White b, then Black fills. Normally Black plays first for some ko threats.