Crosscut to sacrifice

Diagram 1: This is the problem I set last week. Since there is no single easy solution, we will look at a few possibilities and their pros and cons. In fact, there are so many possibilities that the book The Middle Game of Go by Eio Sakata, 9-dan and one of the strongest players who ever lived, spends 62 pages analyzing the situation before White made the decision to play at 1. Another 45 diagrams deal with the possibilities after white 5. As before, we will only look at a few possibilities. The most important thing is to visualize a few possibilities to get a reasonable result.

Diagram 2: For Black the most natural thing is probably to attach to the marked stone--the move that initiated the crosscut. Black 6 then comes to mind. However, this gives White sente moves at 7 and 9--Black has to answer with 8 and 10--before making a light shape with 11.

Reference 1: Instead of 11 in Diagram 2, holding on tightly to the marked stone by defending it with 1 shows little flexibility. After Black exchanges 2 for 3, the white stones are heavy and may come under a strong attack.

Diagram 3: (Black 20 connects at the white marked stone.) The worst thing Black can do next is cut and capture with 12 and 14. The more Black struggles to split White, the stronger White's position becomes. In the end, Black loses his marked stone and has little territory to show for his efforts while White is strong in the center where Black once dominated.

Diagram 4: Instead of meekly following the usual script, Black can play at 6 first before capturing the white crosscut stone. This makes the white marked stone a problem--White can't sacrifice as in Diagram 2 and 3. After black 10, White would like to capture black 6 in a ladder with A, black B, white C, black D, white E, black F and white G, but black H puts white E in atari (leaving only one liberty) thanks to the marked black stone. White has no easy way out.

Diagram 5: (Black 10 connects at the white marked stone.) Therefore, instead of defending the marked stone, White sacrifices it, starting with the atari of 7 and 9 before connecting at 11. After 13, White appears to ensure that he will live by playing at A or he can move out with B or C. Either way, White will have little trouble escaping. However, Black has strong positions on both sides, so he is likely to come out all right.

Diagram 6: (Black 10 connects at the white marked stone.) Since White got so much use out of the marked crosscut stone in the previous variations, Black may want to capture right away with 8. After exchanging 9 for 10 (Black connects), white 11 aims at using Black's weaknesses in the corner.

Diagram 7: Aiming to destabilize the whole white group, black 12 is an aggressive move. White 13 through 17 aim at capturing Black's corner, forcing Black to defend with 16 and 18. Now White grabs his chance to cut through with 19 and 21. The result is that Black bottles up six stones with the moves through 30 while White makes a good shape and weakens the marked black stone.

Reference 2: Extending the marked stone with 1 to capture Black's marked stones, doesn't work immediately. Exchanging 3 for 4 before extending to 5 seems a clever combination, but black 6 captures the whole corner anyway. White must play at 7 if he wants to capture Black's marked stones, but black 8 and 10 are a clever combination that kills White's corner stones. If White exchanges white A for black B first, he is able to play at 9 instead of at 7 and cap-ture the marked black stones.

Conclusion

The reference diagrams show why certain moves that look good are in fact bad. The point of the variations shown is to demonstrate how White crosscuts in order to sacrifice one or two stones inside Black's territory to make a light shape on the outside. Neither player can afford to be too greedy as their positions collapse. Accurately reading the variations leads to an appreciation of various problems, which in turn leads to possible solutions.

Problem 1: Black 1 has the familiar feel of the crosscut. How should White respond?

Van Zeijst is a four-time European go champion and European representative at the Fujitsu World Championship.