Cross-cut

In response to a cross-cut, there are three alternatives: extending, playing atari and extending, and playing atari twice and connecting as shown in Diagrams 1 through 3, respectively. Other possibilities usually lead to risky large-scale battles.

Diagram 1: Last week, we looked at extending your most important stone after a cross-cut. So if Black plays a cross-cut with 1 and 3, you should play at 4 (or A) to defend the marked stone. This is your most important stone because if it is captured Black will gain overwhelming influence in the center.

Diagram 2: Often before extending your stone you want to put one of your opponent's stones in atari, e.g. by playing white 4. Black naturally responds with 5. Next, the combination of 6 and 8 snare black 3. The result through 13 is an example of what could happen--Black is worse off both in territory and influence.

Diagram 3: Sometimes, you want to play two atari (at 4 and 6) before dealing with the weaknesses in your shape, e.g. by connecting with 8. If Black goes for the bait and plays at 9, white 10 becomes sente, allowing White to extend to 12. White's thickness is superior to Black's corner territory.

Solutions to last week's problems

Solution 1A: After Black plays the marked stone and White responds with a cross-cut (White's marked stone), the combination of black 1 and 3 forms a joseki. White has no choice but to safeguard his corner with B, but then black A follows, capturing White's marked stone in a ladder. That gives Black a very good result.

Solution 1B: Simply extending after the cross-cut invites white 2, forcing Black to extend to 3. Black 5 is clever if the ladder is good for him after black 11. If the ladder is not good for Black, he should not play this sequence.

Solution 2A: The position before Black attaches at 1 is the result of a joseki. White 2 can be dangerous as Black cross-cuts with 3. Depending on the situation, White is hard-pressed to find a good response. If he plays atari at 4, Black will counter with 5. White can now connect at 6 or capture at A, but black 7 cuts off White's marked stone, giving Black a large corner territory.

Solution 2B: If White pulls back at 4 to save his marked stone, Black can capture one stone in the sequence through 11, which is harmless because of the position of Black's marked stone. However, if that stone was placed at A, instead of wasting a move to capture at 11, Black can cut at B, followed by white C, black D, white E and black F, putting White in great danger.

Solution 3A: The combination of 4 and 6 form the cross-cut tesuji, aiming at bolstering white 2. If Black extends to 7, white plays 8. Black now must defend his stone at 3 by extending once more to 9. However, white 10 is a strong move. Instead of trying to grab the corner now, Black is better off playing at 11, although this allows White to claim a large corner territory. Black has a strong center position and his corner stone still has potential, so the result is reasonable for both sides.

Solution 3B: If the lower side is more important for Black, he can play atari at 7 before extending to 9. The moves through 14 follow. This is also a joseki, meaning the result is even.

New problems

Problem 1: How should White respond to Black's cross-cut?

Problem 2: Again, Black initiates a cross-cut. How should White respond?

Want to find out more? Come to Ben's Cafe in Takadanobaba,Tokyo (03-3202-2445 or www.benscafe.com), where the English speaking go community congregates every Sunday. You can enjoy free lessons, 11 a.m.-1 p.m.

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