: ( 507)
If Black does not answer White's move at locally at 108, but plays on the lower edge with , then both , and , are sente. Black gains three points on the edge (), but then he loses three points in the centre (). In addition, White benefits and gets sente, and continues with a move at , gaining an additional three points. The Semeai Variation will result in a jigo now.
: (A 570; B 572)
Black must connect solidly. He can neither give atari at (without coming back to thereafter), instead, nor can he take a liberty of White's group, at .