115WS Notcher

115WS  

See table of notchers. Alive, unsettled (with or without ko) or dead?

115WS  

Black plays and lives.

115WS  

White makes ko.

emeraldemon: It seems to me that this is a 2 step ko for black:

symplicity: Actually, this is just an ordinary ko where white has a local ko threat. Whoever wins the ko only has to ignore one move by the opponent elsewhere, just as in a regular ko. In a two-step ko, for player for which the ko is two-step would have to ignore *two* moves elsewhere in order to win the ko.

emeraldemon: Thanks, I had my terms confused. Actually, it looks like white has two local threats.

black finds another threat  

Of course, depending on the situation, black 8 may be a threat, or generate threats around a.