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Writer's pictureTakumigo

Analyzing Methods in Go

This article draws content from a Go discussion in Hong Kong where two players had differing views on a game. The stronger player harshly criticized the moves of the weaker player, but the weaker player countered using AI evaluations.


In Go, it's easier to discuss what's right and wrong in life and death situations and calculations, but judgment is a more abstract area, involving a lot of personal understanding and experience. In the past, amateur players often relied on the answers and insights provided by professionals for matters of judgment, such as what joseki (standard sequences) and openings are good or even. We would also try to consolidate some Go proverbs, like "a ponnuki is worth thirty points." Nowadays, judgment in Go is less abstract because everyone can directly seek answers from AI.


However, the variations in Go are endless, and AI's evaluation of a particular shape and subsequent moves can change depending on the specific situation in each game. This is especially true in the middle and late stages of the game, where it is challenging to find answers solely by learning from AI. Therefore, it is still crucial to seek answers using rational analysis methods in Go, rather than merely memorizing AI's solutions. I believe that due to the profound nature of Go, memorizing AI and analyzing based on Go principles can complement each other in learning.


Below, I will use three Go analysis methods to think about playing Go, hoping to provide reference for the readers.


At this point, which move has higher value, move A or move B?


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The answer is that move B has slightly higher value. Here, I'll try to explain this using three approaches.


  1. The fewer moves required to enclose a territory, the more efficient the process.

The lower right corner can be surrounded with one move, but in the upper right, White still has options like entering at point A.


Actually, the principle of "golden corner, silver side, grass belly" is somewhat similar. It means that fewer moves are needed to surround a corner compared to the sides, so the corner is more valuable than the sides. Similarly, the most moves are needed to surround the center, so even if the central area is vast, its value is less than that of the corner.


In this position, if White plays next, is move A or move B more significant?


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Of course, the lower side is more significant because the upper side is open on both sides. And A, B would serve as a miai.


In this position, if Black plays next, is move A or move B more significant?


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The upper side is more significant because, in the current situation of the lower side, both the shoulder hit (A) and the second-line invasion (B) in the center are miai (mutually exclusive options). "Open on both sides" doesn't only refer to both sides; it can also mean the side and the center being miai.


Returning to the first question, another way to think about it is the second method:

2. Tewari method (Sequence rearrange)


If we assume that point A is a small point in the star position...


We can easily see that the 3-3 point at position A is a large area, and Black's reinforcement here to prevent an invasion into the corner is quite natural.


If Black plays at the komoku (3-4 point), the approach move at point A is similarly significant.


If Black extends with move 1, White can easily revert to the 3-3 invasion sequence.

If Black blocks with move 1, White cuts with move 2...

White still manages to live in the corner with satisfaction.

It can be seen that even if point A is not at the star position, the value of forming a column with move B remains high.

Thus, while extending at point B might not seem significant, analyzing with the Tewari Method can help understand its value.


Lastly, discussing the third analysis method:


3. Stone Efficiency


After Black reinforces the lower right, it can neutralize the White stone at R6, possibly forcing White to sacrifice it in the future. In other words, Black's reinforcement in the lower right has a specific effect targeting White's stones, while the reinforcement in the upper right is just a general move, not targeting any stones. Therefore, the lower right move is more significant.

White played an innovative opening, leaving the 3-3 point after playing an extension. Is Black's move at point A the largest play?


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Yes, a move at point A can significantly limit the effectiveness of White's 3-3 point, making it very valuable. So, even though black stones are sticking together, they have high efficiency.

Next, if it's Black's turn, which is larger: a knight move at A or a nobi at B?


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The answer is B, but here's a tricky question:

Which is larger: a knight move at A or a nobi at B?


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This time the answer is A because a small knight move to secure the corner more effectively to the 3-3 invasion than a large knight move or a jump. Thus, judgment in Go can change due to many factors, and we can only do our best to consider them.


However, the examples above show that sometimes a slow, solid move (nobi, bend, kosumi) can be more critical than seemingly more efficient knight moves or jumps. This is a key point.



Lastly, I want to share a problem from 101 Go (101weiqi.com). Although the logic behind this problem doesn't directly relate to the content of this article, if you've seen this problem, you might not resist playing this nobi. XD


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1 Comment


Philippe Fanaro
Philippe Fanaro
Jul 30

Dope. I think a follow-up article with what happened in one of our games would also be interesting to people.

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