Hideyuki Sakai became a doctor ...

By Rob Van Zeijst

Hideyuki Sakai became a doctor after majoring in medicine at Kyoto University, but instead of pursuing this vocation he applied to become a professional go player and defeated a series of pros during the admission process. He was made a 5-dan immediately. Recently, he played in the final of the Shinjin-O title match against Tomochika Mizokami. However, Mizokami beat him 2-1 to take the title, worth \5 million. Losing the first game in this best-of-three series, Mizokami amazed himself by winning both the second and third games by just half a point. A single slip-up in the endgames of the final two games would have cost him a large purse. That is why it is so important to gain a good understanding of counting territory, positional judgment and the endgame. This is basically one package.

After positional judgment

Last week, we saw that from a very early stage, professionals count territory and assess their positions at virtually every move. The book Positional Judgment: High-Speed Game Analysis by Cho Chikun helps us to acquire this ability.

Diagram 1: Last week, we looked at the game between Cho (White) and Hideo Otake that was given as an example in the book. The game was given from black 41, and Cho argues that it is close at this stage in terms of territory. However, more than territory, the balance of power is important. Failing to mention this, Cho provides no reason why he played at 42, and subsequent moves are omitted in the book. Around move 41, White had three two-point extensions on the third line, 40-38, 6-36 and 32-34, and Cho assigned four points to each, although he says 6-36 is liable to attack and subsequent loss of territory. He also insists that invading at A would not be reasonable.

Let's see if we can understand the flow of the game after 42. According to the book, White's goal was to increase his territory on the left and build center influence. He manages the latter but loses points on the left side, which at the time of the move was 28 points. In the sequence to 61, White loses about 10 points, while Black makes about four points. However, White's lower center position is worth more than 15 points. After black 61, where should White play next?

Diagram 2: Backed by his center thickness, White invades at 62. In the sequence through 79, White's invasion appears to be a great success, but at the cost of his marked stones. White 80 is an exquisite move that allows him to live in the corner. Black connects and captures two stones with 93 through 105, but White has greater center strength.

Conclusion: Unfortunately, this game does not provide a good example for counting territory. However, it still is an excellent game to study attack and defense as there are many good battles and clever tesuji combinations. The book does give insights in counting practices and pointers in working out your next move.

Diagram 3: What is the value of the black shimari (enclosure)?

Diagram 4: White may play 1 through 5 to reduce Black's territory. After 6, the X's form the borders of Black's territory while White can still play at A or Black at B.

Diagram 5: If it is his move, White may start with 1 and reduce Black's territory with 3 and 5. After 6, White can play at A or Black at B. Where is the border of Black's territory? And how many points is Black's territory? According to Cho's book, the minimum value of Black's territory is eight points and the average is at least 10 points.

Solution to last week's problem

Solution 1A: If Black plays 1, his territory expands from the A's to the border formed by the X's, for an extra eight points. The triangles define White's territory, which is four points.

Solution 1B: On the other hand, if White plays at 1, his territory amounts to 10 points, as defined by the triangles, an extra six points, while Black's territory is limited to the X's (A's in Solution 1A).

The difference between Solution 1A and 1B then is six points for White plus eight for Black for a total of 14 points. Check this out for yourself. However, more importantly, in Solution 1A, White's stones are weak and can be easily attacked. They are strong in Solution 1B. This should be your main motivation for playing either of these moves.

Problems

Problem 1: What is the value of Black's formation in the upper right?

Problem 2: How many points is a Black or White extension to A worth?