Never fill your own liberties in semeai. 7-dan must know this rule!

Macisajt made a simple mistake in semeai by filling his own liberty
(I included the right way for White in sgf)

There are no books about semeai yet, but one good book written by
Valerij Shikshin (redrose and roln111 father) is already translated from Russian to
English. You will see it in bookstores soon!

As you see, even high level dan players must learn the common
rules of semeai!