Diagram 1: We also looked at how to count. The three groups shown each enclose four points of territory. To enclose the four points, black group A uses five stones, white group B employs eight stones and black group C needs 11 stones.
Now, try to visualize three-by-three territories to make nine points. In the corner, seven stones are needed, 11 stones on the side and 15 in the center. So, territory is most easily built in the corner, next along the sides and finally in the center.
Diagram 2: Are all of the stones (in black group A in Diagram 1) necessary? What happens if we take away black A, B or C? The position on the right is changed so we do not have to be faced with life and death situations. Let's look at each of the situations where black A, B or C is not present.
Diagram 3: In the first case, White could play at 1 to take away Black's territory. Black can block at 2. Without the presence of the marked stone, however, White would have been able to cut at A and capture black 2. In other words, the marked stone also plays an important role. In the end, Black has three points left.
Diagram 4: In the second case, White would play at 1. Black cannot save his stone A. The best he can do to limit the damage is to block at 2, allowing White to capture one stone with 3. Black has no territory left, but White made a point (by taking a prisoner at A). The result is one point for White.
Diagram 5: In the third case, White could play at 1, threatening the marked two stones. Black had better connect with 2, otherwise White could cut over there to capture the marked stones. Black is down to three points.
Since the shape is symmetrical, you can figure out the rest for yourself. As you can see, all stones are necessary to surround the total territory, but each stone plays a different role and has a different value. In this case, the stones at A and C in diagram 2 played a minor role while B was essential for the wall surrounding Black's territory.
Diagram 6: When teaching beginners, I sometimes give them this position on a (nine-by-nine) board. It seems obvious where Black and White's territories are going to be, and, since the positions are the same, shouldn't they then end up with the same result?
Diagram 7: Let's see what happens if White answers every black move. Black 1 is a legitimate threat to invade White's right-hand corner, while black 3 naturally holds the same threat. In addition, black 5 and 7 are sente (a move that needs to be answered). White 8 is necessary to protect white 6 (otherwise, Black will cut at 8 and capture white 6).
Diagram 8: Finally Black will occupy the center as well with 13. From that point on, the sequence through 21 is roughly the best for either player. White 22 makes no territory--it is a neutral point.
Let's now count the result. No stones were captured, so we count the territories as they are. Black has 29 points and White has 22 points, a difference of seven points.
Diagram 9: What we learned from the previous diagrams is that it is not a good idea to answer every move. So, let's copy every black move with a similar white move and see what happens. Black 1 is then matched by a similar white threat at 2, etc. Now something strange happens--the respective areas change hands either partly or fully. Black's territory becomes White's and vice versa.
Diagram 10: The sequence here would be a follow-up, but as you can see, it would be difficult for Black to win by seven points.
Problems
Problem 2: This would typically be the next formation I would let beginners start with to understand territory. Try to establish the first 10 to 20 moves to get an idea of which moves are important.
Rob van Zeijst is a four-time European go champion and European representative at the Fujitsu World Championship.