Meijin titleholder Cho U was ...

By Rob Van Zeijst

Meijin titleholder Cho U was smiling. The situation had become hopelessly complicated, but that was not the reason he was grinning. It was because he had discovered the inevitable outcome of his battle with Honinbo title holder Shinji Takao. The game was going to be a draw because a triple ko was about to appear on the board. This type of triple ko appears only once every 10,000 games or so and Cho was about to experience it firsthand. Takao was more stoic, but the result gave a good indication of how the strength of both champions compared.

Cho is a great composer of tsume-go (life and death) problems, and in this game he had come up with one of his greatest problems due to the skill of both players. That was probably why he was smiling during the game.

Tsume-go

The purpose of concentrating on solving tsume-go problems is deeper than just finding the answer. One benefit is that you practice visualization, a technique praised for being the key to success in many fields.

Diagram 1: When securing a base or making steady territory, extensions on the third line are great, but the fourth line is usually superior to expand a framework. Another reason to play on the fourth line is balance. Even if the normal move is at A, as in this example, that would put three successive stones (including the marked stones) on the third line. For balance, it is better for Black to play his extension at 1 on the fourth line. Later, Black can develop a moyo (framework) on the right side.

Diagram 2: Here, Black plays at 3 on the fourth line both for balance and to build a moyo. When White plays at 4, Black will play the sequence 5 through 11. Since White chose 12 as his next move, Black could develop the lower side with 13 and 15 and finally defend at 17. Black won this game between two pros.

Diagram 3: Let us now continue with some tsume-go. To capture White's two stones, Black can play at 1, making it impossible for White to escape. If he attempts to do so with 2, Black plays at 3, etc., resulting in what is called a ladder, a common way of bottling up stones. If White plays at J, Black will capture all of White's stones with K. This is straightforward. Problems arise when there are white stones in the neighborhood, e.g., on any of the points A through I.

Solutions to last week's problems

Solution 1A: For beginners, white 1 is good enough. Black 2 is a good move, but White can capture with 3 and 5. Still this is gote (a move not requiring an answer) and Black gets a considerable territory in the corner.

Solution 1B: Stronger players would consider white 1. If Black plays at 2, 4 and 6, White captures three stones with 7 and Black gets far less territory than in Solution 1A.

Solution 1C: But what if black plays at 2 and 4 after white 1. Does this pose a problem? White answers this with a great tesuji (skillful move) at 5. Black needs four moves to capture White's stones while White only needs three to capture Black's marked stones. Therefore, after 5, White wins the battle. Black's nastiest move is at A, which would be followed by white B and black C. This becomes a ko but before Black can capture he needs to approach at D, at E and then at F to win it. This is hopeless for Black.

Solution 2: Sacrificing an extra stone with 1 is a good move for Black. Naturally, White tries to capture with 2. In the sequence through 11, Black is alive in sente. In other words, he has the initiative.

Solution 3: White's best choice is at 1. Playing on the third line (one space to the right) is not bad or wrong, but white 1 makes a better balance.

Problems

Problem 1: Do you recognize this position from Solution 3? It has a weak spot at 1. If the ladder is bad for him, White cannot play at 4 after black 3, because black 5 and white 6 will follow. How can Black now capture the marked white stone?

Problem 2: This complicated situation arose in a game between pros. Two questions: Why doesn't White play 18 at A? And after 18, where should Black play?

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