The number of possible games ...

By Rob Van Zeijst

The number of possible games that can be played on a go board is staggering because of the sheer size of the board. As computer programmers have learned, even the great increase in computing power has not been sufficient to improve the quality of go programs. However, according to an article in the American Scientist last month, that is about to change through the adoption of new algorithms along with the integration of huge libraries. But as our knowledge is limited, we know of no moves at the beginning of a game that guarantee victory in the end. In other words, there is no 100 percent certainty. But do we need to play such a move all the time? Generally, a move in the 80 percent-90 percent range is good enough.

As pointed out last week, a good move increases the value of the stones already on the board. In the next few weeks, we will look at the start of representative games of some of the top players of the 20th century to get some idea of their approach to the game. Style, which is subject to short-term fads, changes with the spirit of the times. Rather than the romantic universal style popular two decades ago, the one most prevalent today is a dramatic fighting style.

Cho Chikun, 51, has been at the top of the go world for three decades. Originally from South Korea but a product of Japanese go, he has won nearly every title at least once and was the first player to make more than \100 million in prize money in a year. His style is fast-paced, territory-oriented and pragmatic. Let's look at a recent game between him and Tomoyasu Mimura, 9-dan. Cho is black.

Diagram 1 (moves 1-28): After white 10, a move at 21 would be joseki i.e. standard in this corner exchange. However, Black switched to 11 to increase the tempo. White could play at A or B, but there is the risk Black would play at C at top right first. Therefore, White tries to seize the initiative with 12 and 14, but Black chooses a variation taking territory in sente, enabling him to come back to 21. Cho's style is to grab territory first and destroy his opponent's influence. White plays 22 and 24 to keep up the pace. Black makes a base at the top with 25 and 27. White 28 sets up a huge framework, but he has left a gaping hole. How will Black deal with this?

Diagram 2 (29-57): Black first cuts into the center with 29, 31 and 33, then grabs more territory with 35 (see Reference 1). His marked stones are weakened, but Black tries to take even more territory with 37 and so on. This looks dangerous for Black, but it is just as risky for White. If White fails to attack Black's stones effectively, he will lose the game. Rather than going for an all-out attack, White therefore aims at cutting off Black's link to the center with 46. This threatens a white move at A to reinforce White's marked stones. But Black keeps taking points with 51 and 53. White then plays 54 to take away Black's base. Black immediately moves into the center.

Reference 1: In retrospect, White should have consolidated his thickness with the clever combination starting with 1. Up to 13, White builds a solid wall and aims at constructing an expansive framework with A. If Black prevents that with 14, White would begin an all-out attack at the top with 15 through 19. At this point, all bets are off, but White is in a stronger position to fight.

Diagram 3 (58-97): In this diagram, Black has two groups of weak stones, the marked ones. Cho's strongpoint is that he is always willing to sacrifice some stones. He also has the ability to miraculously save weak groups, inexhaustibly searches for better moves, has immaculate timing and a great fighting spirit. In the game, White keeps up a good attack, but sidetracks with 90. After 95, Black has eyes around A and B, and after 97, he has eye shapes around C and D. In the game, Black has a safe lead in territory and was able to live on the right side. Black went on to win the game rather easily.

Reference 2: When Black plays at 1 (59 in Diagram 3), he is perfectly willing to sacrifice his three marked stones. If White connects at 2, Black would force 3 for 4, and take more territory with 5. White therefore resists as in the game.

Conclusion: Many players admire and try to imitate Cho's style. However, his flexibility, reading of the board and composed judgment in the face of strong attacks, are matchless. Even pros find his approach and strategy hard to emulate. I recommend that you become a pro first before trying to emulate him.

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