Black in a Tight Spot: The 4-4 Double Low Approach

Today I felt that I need a break from doing life and death tsumegos every day. So I decided to study an interesting position I found myself in quite often during my last games:

Diagram 1

Lucky enough there is an article about it at Sensei's Library. That is the starting point for my studies. Today's post will be mainly about 

a) one of the possible continuations for this situation, the so called attach and extend joseki

b) the questions I feel are left unanswered regarding this joseki at Sensei's Library. 

Hopefully, the coming days will bring blog entries about the answers to these questions ;)

Of course, as always in Go, there are tons of variations, sub-variations and sub-sub-variations to the pattern in diagram 1. 

Diagram 2

All points from A to C seem to be viable options. I will concentrate on A before trying to study B and C as well. 

By the way: In my games I always played B. It did not got well ;)

Diagram 3

Diagram 3 shows one of the most frequent continuations of A in Diagram 2. It is the beginning of the attach-extend joseki. The complete joseki in one diagram can be found at the bottom of this page.

I won't look at in detail on this possible continuation: White tries to push through at A. Then Black B, white C, black D would allow black to capture the marked white stone at c14 by sacrificing black 1 and 3. 

You can find more about that here.

Diagram 4

Instead I want to look at white trying to not let black out that easily. For that she plays the diagonal of 6. Black 7 protects the cutting point at A (if white pushed at A, black at B would create a tiger's mouth around C) and defends the corner as well.

Diagram 5

The final position looks like this. Black seems to live and has escaped into the center. White's group on the top looks alive and well and her group below has formed quite a nice wall. 

White can also try to go into the corner at A. In order to prevent that, black usually plays B. 

I would prefer to be white here, but that was to be expected as white started with superior numbers. 

There are a couple of unanswered questions, though:

1) Ok, black 9 threatens a cut at c13, but can't white play 10 at 11 in order to penetrate the corner? Or at least: What kind of reinforcements would white need nearby so that it could handle the cut and therefore ignore the threat. 

2) White 14 seems a little bit cramped to me. I would have expected it to be placed one step further at k17. 

3) What happens if white enters the corner at A and black had not played B?

4) What happens if white enters the corner and black has played B. 

I will try to find answers to those questions between christmas and new year's eve ;)

Just in case following my ramblings diagram for diagram is confusing, here is the joseki as a whole:

Diagram 6