Last post I started to discuss the AB Adjacent corner openings. In this post I wanted to continue this discussion with a focus on the 'AB-D staccato':
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1]
While it may not seem like much, white now has a number of options that can change the look and feel of the game. With black having cut off the imminent threat of the 1-row, white now has a few options. For one (I), white can put pressure on the lower d&e squares - continuing the original thread. Alternatively (II), white can aim for the center (c3) or some surrounding squares. Or (III), white can direct some attention up the b-file. There are certainly other possibilities, but these are certainly the major lines, each with a different feel and rhythm.
I.
In order to put pressure on the d&e squares, one might think to follow up with 4. c1, but this a bit too passive. For one, white already controls the c1 square. So putting a flat there just loses tempo. Furthermore, it allows black to gain more control with 4. ... e2 or 4. ... c2. While there are some eventual exchanges, this mostly benefits black's position to the detriment of white.
If white does want to continue to put pressure, they can choose to pursue 4. e2:
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. e2]
This adds pressure to both the d&e stones, while creating a familiar grid pattern. At the same time, now a play at c1 would threaten a road with e2-. On the other hand, black has a number of good responses:
4.e2 d3 or 4.e2 c2
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. e2 d3]
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. e2 c2]
In both of these cases, black defends the cut, while adding influence to the center of the board. In addition, these also start to build some potential road threats up the d file or across the 2-row. In addition, the 4. ... c2 response black adds pressure to the c1 square, creating an extra line of defense.
4. e2 b2
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. e2 b2]
This isn't quite as good for black, since the b2 flat is a bit weak and can be captured. And plays elsewhere ignore the road thread.
One other possibility is 4. e2 e3?!
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. e2 e3]
This is an interesting play by creating a counter-cut. It allows easy capture of the e2 piece, with some support, but white can easily re-cut with 5. d3 (or 5.c2), or add immediate threat at 5. c1. There is definitely breathing room and playing space in this line, but both white and black will need to be careful with their plays. While it could be interesting, I'm not sure I would risk either of these lines without a really good reason.
Regardless of this, adding threats creates a very lively and active area, but ignores some broader influence plays.
II.
Instead of continuing a line of immediate aggression, white can opt to build center influence.
The most direct path would be through 4. c3
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. c3].
In response, black could cut with 4. c3 c2.
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. c3 c2].
There are certainly other possible plays, but these are easily the most direct and effectively counter a secure middle for white. At best, white would be forced to follow up with cuts and defenses up the b and c-file in order to gain. This line, as best I can tell, is viable for both players and leads into some deeper territory and cut plays that go beyond the opening plays.
Alternatively, white could extend out with 4. c2
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. c2].
Here, white borrows some support from the lower stones, creates a basic threat against black, and creates some indirect influence on the center. On the other hand black can take direct control, build up the d-file, or create space in the a and b-files. These, however, go beyond the scope of this analysis. In short, though, there are a lot of availabilities.
White could attempt 4. c4, but this is a bit disjointed from the supporting stones, and may give black the ability to take control of the momentum and create meaningful space.
III.
Lastly, white could choose to extend up the b-file, most likely 4. b2 or 4. b3
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. b2].
[PTN: 1. a5 a1 2. b1 d2 3. d1 e1 4. b3].
The prior may be a bit too passive, allowing black to take the center with 4. ... c3 or to extend his diagonal with 4. ... b3. In contrast 4.b3 creates a threat at the center, some influence towards the top of the board, and isn't able to be immediately cut. This is probably the most 'secure' line in terms of influence, but isn't tempo heavy, allowing black to set rhythm a bit and potentially regain tempo.
Overall, this position is quite varied with a fair number of options for both players. Each of these is liable to play that is quite beautiful.
----
Think with mind of air
Listen close to heart of stone
A beautiful game
