Last week, we reported that the players ...

By Rob Van Zeijst

Last week, we reported that the players representing China and South Korea had each won their first six games in the 27th World Amateur Go Championship, and that Satoshi Hiraoka, representing Japan, had dropped a game in the fourth round. However, it was nothing short of a miracle that Hiraoka, the former two-time world champion, went on to claim the title after hanging in and beating the Chinese entry. In the end, Hiraoka scored seven wins out of eight games, as did Tang Wei Xing from China, Tae Won Jo from North Korea and Man Ki Hong from South Korea. However, Hiraoka had a higher number of SOS points. SOS stands for Sum of Opponents' Score and is an indicator of how strong the opponents were. If you want to check the tournament out on the Web, visit: www.nihonkiin.or.jp/amakisen/worldama/27/index-e.htm.

Ko

We looked at a ko that could have a decisive effect on your game last week. This all-important ko is also called tenka-ko or tenka-kikazu. We also established that to play a ko you need ko threats, especially when the ko could be decisive. As there are no ko threats in the beginning of the game, you should not try to start a tenka-ko too early. Let us now look at a game where a ko was about to start. Instead of starting the ko right away, one player moved elsewhere to create ko threats.

Diagram 1: This example is from a game between two 5-dan pros about 50 years ago. The opening, also called fuseki, is interesting because both players played a kakari--an approach to prevent the other player from closing off a corner with two moves, 3 and 6 in this case--before Black played at 7 in an empty corner. White 8 and 10 immediately lead to a great tussle when Black tries to cut with 11, etc. The moves through 19 are a joseki, or standard corner exchange. This particular joseki is called taisha, which is noteworthy for its many variations and possible tricks. With 17, Black cops out of the difficult variations, but White appears to have a trick up his sleeve. He wants to cut at A, but this would lead to a ko he could not win. So what should he do?

Reference 1 (black 5 connects where the marked stone was taken): The usual follow-up after the sequence in Diagram 1 is given here. After black 1, White usually plays at 2 to make Black capture the marked stone with 3. White then grabs the corner with 4 as a ko threat. Black fills the ko by playing where the marked white stone was captured. White then connects at 6 and Black makes an extension at 7 or A.

Diagram 2: However, White has more ambitious plans than following the sequence in Reference 1. He wants to start an all-out ko, but he needs ko threats first. That is exactly what he does with 20 through 26. But Black does not let things slide and meets him head on by cutting with 21 and 23. White now sees his chance and starts the ko with 28. After black 29, where should White play his ko threat?

Diagram 3: White 30 is an excellent ko threat, which Black has to answer with 31. However, after White recaptures the ko with 32, Black does not have any good ko threats--one that is large enough to discourage White from capturing his stone with 33. Therefore, Black has little choice but play at 33 himself. White 34 is a huge move, but black 35 eliminates the bad potential in the left-hand corner to gain an advantage should a battle start there. White continues his attack with 36, leading to an extensive fight in this area. In the end, Black takes a small beating in the top right, but White tries to force things by playing at A, which was followed by the sequence black B, white C, black D and white E. White took a severe beating here and lost the game by a large margin.

Conclusion: Even in the case of a huge ko, keep your head. Just look at the different possibilities and make rational choices. Beginners tend to do almost anything to avoid a ko, or to win it. The reason is fear. The best thing to do is confront this fear and play ko just for practice. Learn from the mistakes you make.

Problem 1: A tenka-ko has erupted around the marked white stone. Black can capture this stone, but what will happen afterward? This is a difficult problem, so consider a few variations. Who do you think will win this game?

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