Go Dojo: Sector Fights

BGJ 134 Summer 2004

Reviewer: Nick Wedd

In the previous issue of this Journal, I reviewed Go Dojo: Contact Fights. Go Dojo: Sector Fights is another module of the same training program by Bruce Wilcox.

The structure of the program

The structure of Go Dojo: Sector Fights is identical to that of Go Dojo: Contact Fights. Like that module, it is easy to install and run, and uses hypertext links in a non- standard way that takes some getting used to. If you already have a copy of the Contact Fights module, you will find it easy to use. It is larger than the Contact Fights module, with 1905 pages. It only runs on Windows.

Sector lines and Sector fights

The concept of "sector lines" was invented by Wilcox in the 1970s when he began working on computer Go, and described in his 1993 book "Instant Go Volume 1". To quote from the program: "A sector line is an imaginary line running between two stones of the same color, anywhere on the board. The line must not pass through any stones or links. The sector line is a generalization of a link, but longer. The property of a link is that it creates a boundary that cannot be crossed by the opponent in a connected manner. The property of a sector line is that it foreshadows a potential link boundary."

Sector Fights are fights about whose sector lines will predominate, containing either territory or weak groups. The early stages of a Go game can be regarded as a succession of sector fights, alternating with contact fights.

The content of the program

The program is divided into four sections, "elementary", "novice", "intermediate" and "advanced". The elementary section defines terms, including "sector line" itself, "moyo", and "grouse" (a grouse is a GROUp enclosed within a SEctor: an appropriate name, because the owner of the sector will hunt the weak group while it will try to fly away).

The novice section covers simple applications of these concepts, and begins to show how they relate to one another.

The intermediate section takes this further, and assumes some reading ability, three or four moves.

The advanced section goes still further. It is aimed at stronger players, with the ability to read up to ten moves, and exercise judgement about other Go concepts. It ends by introducing the "Great Wall" concept, in which you start the game with a line of large knight's moves up the middle of the board. This idea is not Wilcox's, he found it in an article from the 1920s, but he gave it the name "Great Wall", and did a lot to popularise it in the West.

Each section has tests for the reader, to ensure that the material is being understood. I did rather badly on these, though really they were easy enough for anyone who had read the material properly: I blame the need to work through thousands of pages of material in time to meet this Journal's press date. Each section ends with a few games that illustrate the points covered.

I like the way that Wilcox writes. I get the impression that many Go books nowadays are like many cookery books: they are not really intended to instruct, but rather to titillate, providing the reader with chat about, and pictures of, his or her favourite topic. This is not Wilcox's aim at all. He wants to convey concepts, ensure that they are correctly grasped, and show how to apply them. He does this patiently, with plenty of examples and tests.

Here is an example of his writing. "When you attack you expect him to defend. This will neutralize the attacking value of your move. So the value of your move is what else it did in sente. You particularly need that value if he does NOT respond. Rarely is it the case that you can kill him with your follow-up move, so if your move had no other value you just lost a turn." What this says is clear, and even, maybe, obvious. But it certainly wasn't obvious to me before I read it.


Like Go Dojo: Contact Fights, Go Dojo: Sector Fights is good teaching material, and with over 1900 pages, compares very well in value with any book. Unlike Go Dojo: Contact Fights, it contains plenty of material which is original with this author, and available nowhere else. I definitely recommend it.

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