BQM 21 / BottomSide

Black plays first  

Black wants to attack the two white stones from the right, driving them away from Black's weak stone and into his thickness. Trying the direct approach with 1, however, seems to have a hole in it when White springs the combo of 2 and 4. So what should Black do instead?

White plays first  

DaveSigaty: I am most interested in whether White can get away with the capping play at 1. If White can force Black to live along the edge, then not only will she save her two stones but she is likely to get the opportunity to play around both of the points marked a as well (?). The one on the right will help secure White's corner while the one on the left will undermine Black's corner. This would be an outstanding result for White despite the fact that Black would live along the side. So how should Black fight back?

HolIgor: Aren't these two diagrams related? The answer for one depends on the other. If White can get away in the upper diagram, White 1 on the lower diagram only helps. And if White thinks that White 1 on the lower diagram is desirable, shouldn't Black consider this point too? Of course, this attack is from far away, but it will help Black to invade the right corner as well.

I think that the exchange 2 for 3 on the upper diagram is very good for Black. He can be content. The corner is safe, ikken tobi is easy and attacks. All his groups are safe and as yet White is not connected.

Ikken tobi.  

The trouble with an ikken tobi is that White can simply run out, too, and has friends nearby (marked). Also, Black's corner has some bad aji, and Black can't feel good about letting it get hemmed in.

What about a Black boshi?

Boshi  

The general idea is for both sides to run out, and for Black reduce White's potential on the right in the process. White a - Black 4 would play into Black's hands. So the play might go as in the diagram, with a difficult fight.