Su Doku, a game with a Japanese-sounding name but ...

By Rob Van Zeijst

Su Doku, a game with a Japanese-sounding name but invented in New York, has become very popular. The idea of the game is to fill in nine 3x3 grids with numbers 1 through 9 so that each horizontal and vertical row, each individual 3x3 grid, contains the digits 1 to 9. Some numbers have already been provided, and the player must use logic and the process of elimination to solve the puzzle. It is interesting, but its major drawback is that there is always a solution. You may think this strange, but it is limiting in that it does not draw on the imagination.

This is in stark contrast to go, in which you never know if there is a solution to a particular situation, and this stimulates the imagination.

Now let's continue the 2-handicap game that we started two weeks ago between Shunpei Uchida (Black), a 15-year-old 1-dan, and current Tengen titleholder Keigo Yamashita.

Diagram 1 (1-20): Black opens up a strong attack with 1. White seems to be in trouble. However, white 2 through 8 is a great combination. Black cannot stop White from extricating himself. Finally, it is Black who is in trouble when White moves out with 20, splitting Black's group into two weak parts.

Diagram 2 (21-58): Despite this, Black keeps up the attack with 21 and 23. But White then strikes with 24. Black's defenses start crumbling. White builds a huge wall in the center while connecting his group with 37 through 57, and captures the marked stones. This is a disaster for Black. Next week, we will see what happens when Black invades White's area at the top.

Hints for improving your game

Being foolishly consistent is, of course, stupid. But what about being foolishly inconsistent? Many weaker players are afflicted with this "disease."

Diagram 3: In this four-stone handicap game, are you familiar with the joseki up to 11? If Black wants to increase his center thickness, the sequence 12 through 18 is good. However, 20 is a strange move and allows White to make a strong move at 21.

Diagram 4: What should Black have done? Playing at A is good for Black, but if he wants to build a wall, he should follow 1 through 9. White 10 seems like a strong move. However, White's territory already extends to the Xs and will only expand to the triangles, giving him about 9 points. When Black answers with 11, his territory and influence, indicated by the squares, is about 18 points.

Solutions to last week's problems

Solution 1: Throwing in with 1 to sacrifice one stone is a clever tactic. White must capture with 2, but after black 3, White cannot fill in the hole. His best continuation is 4. Now Black can capture the ko with 5 (where black 1 was taken). Instead of 1, Black could also have started at A.

Solution 2: If Black does nothing to restrain the marked white stones, White will strike with 1 through 5. After this, White cannot fill the ko, so his best option would be to play at A. However, White would then start this complicated two-step ko by capturing black 4. Note that making the exchange A for B would be disastrous for White.

Reference 1: The sequence shown here was used as the base for the problem of Solution 2. When Black plays at 3, the combination 4 and 6 is dangerous. However, Black sacrifices an extra stone at 9 to make great shape with 11, 13 and 15. White now has to add a stone in the corner.

New Problems

Problem 1: After 15, where should Black play?

Problem 2: A move around A looks like a prime candidate for Black next. However, that would be a mistake. Can you think of a move that would make all of Black's stones work together?

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

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