Real Game Tsumego 3

Hey there!
Sorry, I have not been very active here recently but now I will show you another interesting problem, which occured in one of my Insei-games.


Dia 1:


This position occured in one of my games during the last weekend. The marked group of black stones on the left side seems to be dead. If White can kill this group he will win the game for sure.
Let's find a way to do something here.
















Dia 2: Directly trying to live is not going to work.

Of course you will have noticed by now, but in order to make sure that everybody understands why the group on the left looks dead locally I will add this diagram.
If Black plays 1, White will counter with 2, Black can't connect at A because of a lack of liberties. Therefore when Black captures at B, White will take his second eye with A.












Dia 3: Aiming for Whites shortage of liberties


The Sagari in this diagram is a nice move. Now White is just a little short of liberties, so he has to begin to capture the two black stones with 2 here. After this 3 is a great Tesuji for making life with the main group.















Dia 4: Whites failure:


If White simply continues to take Blacks liberties, Black can force with 2 and 4. If Withe after this captures at A, Black can live unconditionally with B.

Can White do any better than this ?-



















Dia 5: Best plays for both sides


To make a long story short: The best White can do is to start a Ko with the combination of 1 and 3. Still this Ko is pretty dangerous for White, because Black will take first.

Note that White 1 on 2 will not work as White will only have three liberties in this case, leading him to lose the Semiai.