16. A Ko That Suddenly Vanishes
The Taisha: A Difficult Joseki

by Richard Bozulich

The position in the problem below arose from one of the difficult variations of the taisha joseki. Nowadays the taisha is almost never played, at least not the difficult variations, but it was quite popular in the 18th century up through the 1970s. To understand why it is no longer or rarely seen in professional go, see Shibano Toramaru's book Joseki Revolution. In any case, many interesting ko variations arise in the hundreds of variations of this joseki. The one below is particularly interesting.

White to play
Problem. White to play
Black has just captured with 1, starting a ko fight. White doesn't seem to have any good ko threats, except to make life with his group in the upper left corner. But that would be submissive. On the other hand, White has a brilliant move that resolves the ko and completely destroys Black's position.