But doing something without knowing the purpose sometimes sets you up for something bigger. In this series, we have captured stones and explored various techniques to achieve that end. At best this is a means to an end, but it is not the purpose of the game of go.
The goal
The purpose of go is not to kill each other's stones, but to surround territory. So how we go about this?
Diagram 1: Let's look at the end position of a game. Both Black and White have surrounded points. Before counting, we first have to establish there are no profitable moves left to play. It is obvious that wherever White plays within Black's territory, his stones will die.
Diagram 2: What about Black? If he plays at 1, White answers with 2. If Black moves at 3, White plays at 4. In response to 5 and 7, White plays 6 and 8 to capture these two black intruders.
Diagram 3: So, White's groups are safe. Black has surrounded the points A through L and White the spaces from M through Z. Black has 12 points and White 14. In other words, White would win by two points on the board.
Diagram 4: Can't Black play the moves in Diagram 2, forcing White to play stones in his own territory? After the moves played in Diagram 2, the final position looks like this. The two stones (where the triangles are) on the left have been captured already, while the two marked black stones can't escape. On the other hand, White can capture them whenever he wants, so they are dead. Dead stones like these should be taken off the board at the end of the game after all moves have been played.
Diagram 5: Let's count the territories again. Black's territories haven't changed, but White's have, as they add up to only 10 points. However, White also captured four stones. The total adds up to 14 points, exactly what we had in Diagram 3. In other words, the total score for each color is the number of territorial points in addition to captured stones, if any.
Solutions to last week's problems
Solution 1: White must not fight a ko because he has no ko threats, and Black would just capture the ko in his first move and the marked white stone in the next. White 1 is not merely defending, as it creates cutting points at A, B and at 4. Black 2 defends two cutting points, but White is already alive and can take the lower left corner, e.g. with the 3 and 5 combination. If Black plays at C or D, White will capture a stone with B. Black can also connect that stone by playing at B or E, but then white C makes life.
Solution 2: After Black captures the marked white stone, White should capture the marked black stone. This is a funny situation called double-ko, where Black can win one ko but will lose the other. He cannot win them both to kill White.
Solution 3A: After black 1, White should play at 2 and sacrifice one stone with 4, then clamp at 6. Black's strongest move is at 7. However, after black 9, White can either capture the ko (by playing where his stone has been taken at 2) or he can play at 10. Either way, the situation is ko, as you can see in the next diagram.
Solution 3B: If Black connects at 11, White captures the ko with 12 that is also atari on the four black stones to its left. If Black saves those four stones with 13, White ensures life with 14.
Solution 3C: Black should have slid to 3. The moves to 9 are optimal for both parties, but in the end, White will die as he cannot make two eyes.
Solution 4A: White should counter black 1 with 2 to stay in the game. If Black answers white 4, he will end up with losing by three points (excluding any komi).
Solution 4B:There are many possible variations, but whatever happens, White has to block at 2. Many intermediate players know the tesuji (clever move) combination of 3 through 7, but it often backfires as shown by white 28. In the end, White wins by five points.
Want to find out more? Come to Ben's Cafe (Tel: 03-3202-2445 or www.benscafe.com) in Takadanobaba, Tokyo, where the English-speaking go community congregates every Sunday, 11 a.m.-1 p.m.
Rob van Zeijst is a four-time European go champion and European representative at the Fujitsu World Championship.