Unusual three-stone enclosures
Based on the 4-4 point:
The most common way for White to invade here is at a.
This doesn't seem well co-ordinated as far as taking the corner is concerned, but is seen in pro games.
If pros now make these enclosures, against traditional teaching, there could be several reasons:
- try for extra territory, despite worse aji;
- play a move more distant from the corner as a more effective checking extension;
- invite an invasion for useful thickness.
As part of the 'Korean style' (also seen in players such as O Meien), the use of this enclosure is probably more often because of reasons 1 and 2.
The 3554 enclosure is also a source of several unusual three-stone enclosures.