In my games is often played . I have not found this move in joseki dictionaries. What is wrong with this move? What is the best answer? --!Uwe
White usually plays . The purpose of this move is to prevent Black making good shape, at the same point. Then Black usually extends to (or a or b) and White extends to or c. This position is considered slightly preferable for White as the corner is still open for an invasion at the 3-3 point.
But if Black already has a stone in the region of , the kosumitsuke is recommended.
After and , White can extend as far as , a perfect use of the wall + (see extension from a wall). Therefore this way of playing isn't usually considered joseki for Black, unless there is a further black stone on the upper side that interferes with .
Here White has to undertake something to settle her stones while the black stones flow naturally from both sides.
(For more details, please see 4-4 point diagonal attachment joseki and 4-4 point diagonal attachment, one-space jump (without pincer).)