Herman: Correct me if I'm wrong, but isn't this a better defence for white? Now black's invasion has become pointless, and white gets 7 points, winning by 2. (Black must play at least one of the a marked points to prevent another point for white there)
You're right! Even more reason for B not to play this line. SiouxDenim
W cannot defend both attacks, so uses half a move to defend the cut and half a move to make an attack on the bottom B stones.
Herman: Shouldn't white's second half move be at a? That way, white can live and will not lose any stones...
Herman: Whoops, missed that :)
So how about this then? White will either make three eyes on the left, or get both moves a and get an eye there...
It's not easy this problem making malarky! I added the 3 White stones on the right to provide some threats, they weren't supposed to be an option for an eye :( I can't find an easy fix for the problem either. SiouxDenim