The Magic of Go

Japan-China Tengen match

With a first prize of 10 million yen, the Tengen title is the fifth most prestigious in Japan. Chinese go players also compete for their own Tengen title, and it ranks among the top three titles in China. Every year, the Japanese and the Chinese Tengen titleholders meet in a best-of-three match. This year was the 12th year this series was held. China has won this event in the past eight years, while Japan won it in the first four years. Incredibly, during the eight-year Chinese winning streak, this year was the first time the Japanese Tengen titleholder managed to win a game.

This year’s match pitted Chang Hao, China’s top player, against Koichi Kobayashi, Japan’s No. 2 player. Although Chang won the match by winning the first and third games, it was a close and filled with excitement, especially in the first game.

Every year, the venue of the Japan-China Tengen match alternates between China and Japan. When the match is held in Japan, Japanese rules are applied, and when held in China, Chinese rules are used. This year, it was China’s turn and the match was held in Shanghai.

As I explained in an earlier column, Japanese and Chinese rules are essentially the same. The difference is that only the territory is counted under Japanese rules, while both the stones and territory are counted in Chinese rules.

Under Japanese rules, the game officially ends when both players agree that the last point of territory has been taken. After that, all the neutral points are filled in and the score is determined. If a defensive move needs to be made inside one of the player’s territory and that player does not notice it, it will be pointed out to him and he will not be punished for his oversight. Under Chinese rules, since the stones played are also counted as territory, the game is not over until all the neutral points have been filled in.

In the first game of this year’s match, when the last point of real territory was played, Kobayashi, who was playing white, was winning by half a point (Note that at the beginning of most tournament games, Black gives White 51/2 points as compensation for moving first. The extra half point precludes draws.)

go game

Figure 1 shows the position at the end of the first game. White connected the ko in the upper-left corner with 1. Under Japanese rules, the players would probably agree that the game was over, so White would win by half a point. Under Chinese rules, however, the game continues with the neutral points being filled in.

After Black 6, Kobayashi carelessly played White 7. Chang immediately replied with Black 8 forcing White to connect with 9, then cut with Black 10. White’s position here has now collapsed. There is no way for White to avoid a large loss, so Kobayashi gave up.

If this game had been played in Japan, White would have been allowed to make a defensive move to defend against Black 8 and 10, even if he had not seen it. But since the game was still in progress under Chinese rules, White 7 was a mistake so Kobayashi had to suffer the consequences of a loss of more than 15 points. Can you see how Black can capture some white stones? The answer will appear in next week’s column.

Current tournament news

On May 10, the third game of the 3rd LG Cup final best-of-five match was played between South Korean prodigy Lee Chang Ho and Ma Xiaochun of China. Lee won the first two games of the match last March, so Ma had his back against the wall and could not afford another loss. But, as it turned out, Lee proved to be too strong and forced Ma to give up after 159 moves. This is the fourth consecutive international title Lee has won in the last year and represents the grand slam on the international go circuit. His run started last year on May 13 when he beat compatriot Yoo Chang Hyuk 3—1 in the Tong Yang Securities Cup. He went onto beat Chang Hao in the Fujitsu Cup final on Aug. 1, then defeated Ma in the Samsung Cup 3—2 on Feb. 8 this year.

The first game of the 54th Honinbo title match between titleholder Cho Chikun and the challenger Cho Sonjin was played on May 12 and13. The first game went as expected with the Honinbo getting the advantage early and keeping it to win by 61/2 points.

Answer to Problem 2

go problem

In Problem 2, White has played 1 threatening to capture the two black stones at the top. This has become a capturing race: the white stones and the black ones have three liberties each. Since it is Black’s turn to move, he should be able to capture the white stones. For example, Black might play 1 in Diagram 1, but White will turn at 2, threatening to capture the black stone at 1 by playing at 3. Therefore, Black must defend by connecting at 3, and White can play 4. Now White is ahead in the capturing race with three liberties to Black’s two.

go tactic

After White 2 in Diagram 2, Black can create confusion by playing 3. White ataris the black stone at 1 with 4, but Black counter-ataris with 5. When White captures with 6 the situation has become a ko. Black does not need this complication.

Black can resolve the situation in the corner by playing Black 1 in Diagram 3. This skillful move is an example of the «belly attachment» tesuji. Once this move is played, analysis of the position is easy. The problem is seeing this tesuji in the first place. White has two options. The first is White 2 in Diagram 4.

go tactic

This move prevents Black from linking up along the right side, but Black can link up to his two stones at the top with 3. The atari of White 4 is not of much help; Black simply connects with 5. White 6 does not help either as Black blocks at 7. The capturing race starts in earnest with White 8, but Black is one move ahead and he captures four white stones with 11.

If White blocks the linkup along the top with 2 in Diagram 5, Black links up along the right side with 3. The capturing race begins with White 4, but Black is one move ahead and captures three white stones with 7.