Whenever arranging information, ...

By Rob Van Zeijst

Whenever arranging information, you inevitably run across the problem of what to put first and what comes next and so forth. Of course, classification by chronology, type, alphabetic order, and other classes come to mind, but especially when the information is changing all the time, importance often forms the top priority. But what is important? Separating the signal from the noise, basically, is the problem that faces us every day. A game like go with its many possibilities represents so much information that it is difficult to know what is important. Often there is a multitude of important issues floating around that need to be dealt with based on priority and urgency. If you are already playing at the dan level, you can often improve your go instantly by thinking more about priority and urgency.

Diagram 1 (1-31 represent 61-91): Let us resume the game we started two weeks ago between titleholder Keigo Yamashita and challenger Kobayashi Satoru (Black) for the 41st Kisei title match.

At this point, Black's two marked groups are in danger, while he is aiming at cutting off one of White's marked groups with A and another group around 2. At the same time, Black must also attack White's two marked stones in the center. Why must he do that? You know the adage "attack is the best form of defense," but why is this true? Pros, for example, never like to just run away because that is a shortcut to defeat--they always try to somehow find weaknesses in the opponent's position and exploit them, because groups are only weak relative to the groups surrounding them.

Anyway, black 1 strengthens Black's center stones and threatens to cut, inducing white 2, in turn justifying black 3, which reinforces Black's position on the left. This, however, gives White the chance to hit back with 4. Black 5 and 7 are a strong combination, aiming at cutting at A. See reference 1. White 10 is an important next move, because it is the vital point to make eyes for both White's group and Black's stones. Black now has no choice but to get out with 71. Now that Black's large group on the left is safe, the next priority is his group of marked stones on the lower side, so White plays at 12 to connect them. Black next plays 13 and 15 to cut White in sente, taking the initiative. Now, having weakened White's position as well, Black moves out with 17 and 19, urging White to connect his marked stones with 20. Next, Black reinforces his stones with 21 through 25 while putting pressure on White's center stones. Of course, White runs out with 26. However, black 25 was in fact a bad move. He should have played at 26 himself.

See Reference 2. After Black's timid move at 25, however, the fight does not quieten down. In fact, the gloves come off completely and both Black and White have a number of weak groups that are all struggling their way to safety.

Reference 1: After black 3, if White blocks Black's way out with 4, Black can connect with 5 and 7 while cutting off White's stones. This is out of the question for White. Incidentally, before defending at 3, Black should exchange 1 for 2 as in the game. If he defends first at 3, afterward pushing at 1 will not be answered at 2. In that case, White will give way with A.

Reference 2: Black should trap White by playing 1. If White tries to fight his way out with the moves through 12, Black prevents his surrounding stones from being captured with 13, 15, and 17. White 20 looks severe, but Black is out after 21. Should White try to capture with A, black B, white C, black D, white E, and black F, Black can escape while White's stones around 2 die.

Diagram 2 (32-63 represent 92-123): After 32, Black cuts with 33 through 41. The combinations 38 and 40 as well as 37 and 39, and cutting at 43 are all quintessential pro moves. The fight keeps going on with a multitude of drifting eyeless groups. Although it is nerve-racking, both players like this kind of go, while it is very exciting for the spectators.

Solution to last week's problem

Solution 1: All of the moves 1 through 20 in Diagram 1 epitomize the importance of the various marked groups involved and the order of priority.

Solution 2: Usually the first thing to consider when trying to attack is how to limit eye-space--black 1 does just that. White 2 is the vital point but black 3 and 5 take away White's second eye. Now black 3 is connected with either A or B.

Solution 3: Black 1 limits eye-space and black 3 is the vital point for making two eyes, and by extension, taking them away. White 4 and 6 are White's strongest moves, but black 7 is clever because it puts White in damezumari--a lack of liberties--as White cannot play at A.

Reference 3: Black 1 and 3 look like a good combination, but this spells failure as white 4 and 6 are sente. If Black insists and occupies the vital point with 7, white 8 cuts off three black stones. Conversely, if Black plays at 8 or A to defend his stones, White makes two eyes with 7.

Problem

Problem 1: White plays first and must try to kill the Black stones.

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