Territory Example 1

Territory  

The position is from the first game of the 2003 Kisei between Yamashita Keigo and O Rissei. Yamashita holds White.

1. The black left is secure territory.
2. The black lower right is also territory, but his group is surrounded. If White gets both a and b, Black may have to play inside his territory. The left does not feature such a problem, except of course if White were able to push through at c then d after a ko. That is quite unlikely to happen.
3. The black top is not territory but a framework close to becoming territory. In fact, due to Black's attempts to cut down White's huge moyo to size, his own top was successfully invaded.
4. The white center right is not territory but a large framework.