4-4 point low approach low extension, contact
White plays in order to strengthen the lone stone. Of course Black will expect to become stronger here too: Black at a is probably automatic unless is played as a ko threat.
This variation is normal in contemporary pro games. Next White plays a or b, depending on the position on the upper side and the need to protect her shape.
Black can also play at to trade the corner for a position on the upper side.
There can be a number of ways to play this variant, but this is a representative sequence, with White alive in the corner.
In recent years White has tried the immediate cross-cut at , raher than the staircase, presumably to avoid this development.
It is also possible for Black to connect solidly with (according to the advice about the staircase). Both groups then have good shape, and Black may want to make a flanking extension immediately on the left side.
With the knight's move extension, the double hane (osae) is a rare play in pro games (differing from the case of at a). There is probably more than one reason for that: White at b can be helpful if White is looking for sabaki here; there is feeling that Black is being forced into Overconcentrated shape, too.
White's other idea is to play here for a bulge formation. Black probably takes up the challenge of a ko after and . The steady play of at a is also seen: White can still provoke a ko with White at b, , , but this ko is a little better for Black.
The crosscut doesn't seem to be mentioned at all here. Is it horrible? If so, what is white hoping to do to black? I suspect white at "a," after connecting, to make sabaki as above, but I'm not really sure how that would go. In fact, the only variations I can come up with seem really good for black. -jettero
(4k): White connects out of the atari. Black picks which stone to worry about, or .
jettero (10k): Yeah, that is more or less what I came up with. But the very strong player at my go club sometimes uses this patern (to come up with the shape shown in the figure marked "solid connetion") in handicap games. He says it gives him something solid he doesn't have to worry about.
The problem I'm having is that your square stone is not in trouble in a handicap game because the ladder is broken. Now I can't help but wonder what wonderful sabaki he would come up with if I crosscut -- which means I'll probably try it the next time I play him...
This looks awful for black. is too close to black's other stones. is a donation. White is comfortably settled.
Here has been cut off. threatens to capture in a net at a. is one way to escape, but white has made black induce which is a nice play for white. White's danger level on the top looks manageable. This looks ok for white to me anyway, but I'd be happy to have my misimpressions corrected. :)