Xuanxuan Qijing Problem 246 / Solution

Solution  

Black is alive after .

White's follow up  

In terms of tsumego, the best white can do is a gote seki. (In real life, the lost at around 'a' might be more than the seki.)

 

Resisting with doesn't work. After , black has 'x' or 'y' .

First Line Hane

 

First line hane in tsumego problems are important. Very often they stop some opponent stones from escaping. The most common form would be stopping "three-in-a-row" like here.

 

For example, it looks like reduces the black group into an L group, but it doesn't work.

 

Neither does here kill.

More information about the last two diagrams can be found at L+1 group.