Pushing Battles in Joseki 8 Corner Aji Discussion
This position arose for consideration on pushing battles in joseki 8. Here may well have been an overplay; but how does White show that, from this position? White at a is naturally an important resource.
Those with the Korean version of the Igo Daijiten handy will be able to turn quickly to variations 6770 and 6771 of volume 2.
Aji and usage
togo: Not only a is interesting. There is useful aji for the other direction. Note, that , , , are all forcing plays.
togo: ... It also can give sente, when not. in this example has some endgame sente.
togo: There is also benefit for the regular closing-the-skirt play: and make it very much more sente. If Black had crawled one move more instead of , this would only be about the corner, not the whole group.
Note, that not all moves before have actually to be played; but without Black could answer the skirt close on the left with a skirt close on the right (The corner would be still unresolved, but the Black group then lives.).
Lost move, bad shape
togo: Anyway, already the necessity of is bad, it is a lost move.
Also the resulting black stones are in bad shape, exploited by White in this example ( in the given example is better than at a. If at a, then at at at b.).
Note, that with playing the aji sequence first White at c or d later are sente moves.
Compare this with ...
togo: ... this similar situation with different . Of course can also be at or at or at . What is important, is that Black here has one move more and better shape (In addition to White not having that big aji).
Extension instead of hane
togo: Also compare with this situation. Again does not hane. The jump-ahead can be thought of being prevented by the early hane.
here is on the same position as the original . As with the original situation Black has played another stone to prevent capturing of important stones.
has somewhat the same role as the original , but is already in place. Nonetheless this situation seems better for Black.
togo: Another continuation when is not the early hane.
White's keima can be cut. This sequence again follows roughly the idea of the original early hane. And again Black has played another stone to prevent capturing of important stones.
Now has a similar role as the original , but is already in place. Nonetheless this situation seems better for Black.
togo: The skirt close is not that sente without the extra aji: Only the corner now, not the whole group.