KarlKnechtel: Does b really capture the stones?
And I prefer capture B over capture A in the original diagram.
I suppose that since this diagram is drawn on the edge of the board, it will work eventually. But this certainly doesn't seem like as tight a grip as the geta offers, since that captures after at most three attempts at resistance by White.
Now Black is really in trouble, if he does not give up this plan of attack. Seems like White should be able to find some escape here.
Now White has both options - a loose ladder with a, or four liberties with b.
I think Black can capture even without using the edge. - Migeru
Charles Why? After White a, Black b White can just play c.
Migeru I see. What if Black had a stone at d?
Charles It is still no good for Black.
Gregory: I take Kageyama's point to be that b is more firm than a, because if black plays a and white plays b then c and e become cutting points when black plays d.
For example. Of course whether or not the cuts or cut threats are valuable will depend on the other positions on the board.