4-4 Point, Double Low Approach, Kosumi
Charles Matthews This diagonal play has experienced a revival in pro games, associated with new thinking about central influence and possible tenuki variations.
After here,
at the 3-3 point is normal; and now Black plays a, b, or tenuki allowing White at a.
The problem with this joseki for a weaker player is that Black at a can leave a black wall, but without a pincer attacking and also with some potential shape problems. Clearly this isn't troubling at pro level, but amateurs can come to grief here.
After Black's main options are at e, f and g. Playing g, which is a move useful in handicap games when Black has a stone already at the circled point to attack
, isn't very forceful here. Black at e is only seen in old games.
After , black cannot tenuki. White's shape is too good after
,
. If black wants to tenuki, it should be before
, not after.
Probably is the best idea here, but the bulge play
gives Black some shape difficulties.
In games of Hane Yasumasa based on the Chinese opening ,
,
was used to build influence for Black on a large scale, treating the cutting point at a as secondary.