In this age of computers, ...

By Rob Van Zeijst

In this age of computers, robotics and software development, it is easy to believe computers can do almost anything. However, even the most mundane tasks for humans, such as dressing ourselves, making breakfast, or just walking, pose immense obstacles for robotics. Visual recognition, navigation and machine learning are the toughest challenges in robotics, and while competitions make clear there is huge progress, basic problems remain, according to Microsoft Corp. Chairman Bill Gates. That is the coordination and processing of data from multiple sensors and other inputs that provide information about movements in a changing and interactive environment. The simultaneous processing of these data and sending appropriate commands to make the robot move accordingly is called concurrency. As Gates tackles concurrency problems by writing appropriate coding, he hopes to ignite the spark in robotics that Basic provided for the computer industry. Meanwhile, we have our own concurrency problems with go as we apply fuzzy logic to match our knowledge with interactive situations that are always unique.

Diagram 1: We will now continue the game we started last week between titleholder Keigo Yamashita and challenger Kobayashi Satoru (Black) in the 41st Kisei title match.

After White crosscuts with the marked stone, Black has a few options (see References 1 and 2). However, he does not want to waste his own marked stone--he wants it to work in synergy with his other stones to attack White's stones. That is why he chooses the sequence through 13. Soon after, Black cuts with 23 to establish supremacy in the center. However, White ignores this and invades with 24 and 26, forcing Black to defend the left side in the sequence up to 31. Now White is ready to take the fight to the center with 32.

Reference 1 (black 15 at 3): In response to the marked white stone, black 1 is the usual move. The moves through 15 (played where his stone at 3 was captured earlier) form a joseki (standard exchange). However, this is not so good because White can play at A or B to cut off the marked black stone. White can also play C and D in sente (Black must answer these moves) and aim at a strong invasion at E to cut off Black's marked stone there.

Reference 2: The moves 7 and 9 initiate a relatively new joseki that becomes complicated when White cuts with 12. This will lead to a tough battle. However, the bottom line is that Black's marked stone is not exactly in the correct spot, meaning this will almost certainly be a lost move.

Diagram 2: Let's evaluate this position for a second. Black is threatening to play A, which would be followed by white B, black C, white D, black E and white F to start a ko, putting all of White's marked stones in jeopardy. He must be sure his two marked stones in the center can escape--that is already a problem in itself. At the same time, Black's marked stones on the left are also in danger as White can play at G, followed by black H, white I, black J, white K, black L, white M, black N and white O, leaving Black dead locally. He can escape, but the problem is can he do so with all of his marked stones?

Reference 3: Black can also cut with 1, 3 and 5. White 6 and 8, however, are a brilliant tesuji leaving Black with just four liberties after white 12. White's marked stones have four liberties, too, and it is Black's turn. However, Black cannot take away these liberties in this situation. He needs to make at least one move to approach. So, Black loses the semeai, or capturing race.

Solution to last week's problem

Solution 1: Diagram 1 gives the correct response to the problem of what to do after White makes a crosscut with the marked stone. References 1 and 2 supply additional insights.

New problems:

Problem 1: Try to combine all the things discussed concerning the various marked stones and groups. Set the priorities, analyze the variations and decide what Black should do.

Problem 2: When solving life-and-death problems, some things you should think about are expanding or confining the eye-space, vital points, tesuji, liberties, etc. Establish which ones are important in this problem and determine how Black must play to kill the White group.

Problem 3: How should Black use the criteria mentioned in Problem 2 to kill the White group.

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