TFG9 Black Upper Left
First let's look at some simple questions... DaveSigaty
What if Black just connects?
This eliminates the opportunity for White to throw in here and squeeze Black. White plays to spoil Black's eye but when she answers with , Black sets up a ko for life on the left with the opportunity to capture White in the upper center still open. White can't win this way.
- is a strong play
- If , White answers with which threatens to cut at and at the same time reduces Black to one eye. If Black tries to cut at , White answers at . If Black persists with , sets ups a situation where Black is in shortage of liberties on both sides ( Black a, White b). White can capture the left side stones before Black can free himself at the top.
- Black varies to to prevent White from cutting at a.
- So White turns to the upper side to increase her liberties.
- So when White plays , the inner shapes are the same on both sides, but White is one move ahead, winning the fight and the game.
The variation in 2c above needs to be revised to reflect an improvement for Black found on TFG9 - White At The Top.
Continuing from 2b, Black plays instead of the original . When White throws in at , Black extends at . Although White takes the stone at , the space inside her group is much smaller than in the original line and she ends up with only five liberties. She has the ko but since the real issue is the survival of the black group on the left, Black has more ko threats than White.
at . After , Black is two moves from capturing the white stones while on the left White is four moves away from capturing the black stones. Black also has the internal ko threats of a and b. White's position is hopeless.
Someone else's turn to post a few lines!
- What are the refutations for the a points below?
- Are there other lines as well?
- What if Black doesn't start with the / exchange?
Arno: the points marked as a suffer from a follow-up play White b which will lead to the capture of the crucial stone. That way White will increase her liberties and whatever Black tries, he will fail.
But there exists another line: TFG9 Black Upper Left 2.