Angle play after diagonal attachment
The problem is with . I (Charles) see this often when White enters Black's sanrensei. Black can get good territory by playing at a; while in a handicap game playing at b for influence is also good.
If White really wants to make a base, playing is better. The common play is c, but that can mean that White is driven out into the centre.
Charles is fine, but is a bit heavy: try at a (or even b) instead.
From Takemiya Masaki-Jiang Zhujiu 1988-08-21. Here takes into account the earlier exchange of and to the right. White lives quickly (White 11 at d) and claims that Black is a little overconcentrated to the right. In return, Black can claim greater security on the left: to invade at e and get the answer Black f is seemingly a bad idea for White, seriously weakening her side group.
 Why is bad? Please show an example.
In answer to , Black has a choice of playing at in this diagram, or this sequence to give White bad shape.