Li Changho Jingjiang Weiqi Shoujin / Errata
The book solution is just ,
,
. But after this, if
at
, then
may not be easy for beginners to find, so it should be mentioned in the solution.
In the first solution diagram, and
should be played in the opposite order,
first. (The next two diagrams show why
first fails.)
In the book's solution diagram, is a mistake, and should be at a instead. White sacrifices
to prevent
from connecting out. (According to KataGo, this may actually be the best play for both sides in some full-board positions, but it doesn't achieve the problem's goal of connecting.)
If black does need to connect out, is the way to do it. After
and
, if
at a then
at b catches white in a shortage of liberties.
The book gives black a as the solution, and black b as a mistake. In fact, black a fails: white can escape by playing either b or c.