Beginner Exercise 12 / Solution

Sub-page of BeginnerExercise12

One should know that there are two ways to tackle a life and death problem of killing a group with a large eye space.

  1. Reduce the eye space until it is small enough to be killed.
  2. Play directly at the vital point inside the eye space.

Normally, the easier way is to try method 1. But if method 1 does not work, then we would have to consider method 2 instead.


As a simple analysis, we see that merely capturing at B1 is not enough, as W2 lives with a straight four. So we have to go deeper into the eye space.

Reducing the eye  

We begin the discussion by trying method 1, which is to reduce the eye space at B1. Naturally W2 captures the two Black stones...


... and at the same time, we see that a and b are miai for life. So we can conclude applying method 1 in this problem fails.


Now we look at B1, which applies method 2. Indeed, this is the solution for this problem.


The W2 simply captures a stone, then B3 kills.


What happens if White plays W2? B3 is neccessary to destroy the eye...


... and B5 makes another throw-in, leaving White with a false eye. This completes the discussion of the problem solution.


However, please note that not every point inside the White's eye space is a vital point. B1 here is not the vital point, W2 is.

Reading exercise  

If you have followed the discussion so far, then you might also know that B1 is also not a vital point. The best W2 for answering B1 is... I leave this as a reading exercise.


Karl Knechtel: So it seems. :) Though, doing tsumego and solving the problems in an actual game are different matters, at least for me. For big battles where the goal is to connect or to cut an opponent's connection, I seem to do fairly well for my strength, and I'm all right at destroying eye space and making good shape. But I have a horrible time of it when the group whose life is in question is isolated; if it's mine, I'll misjudge it as already alive; and if it's the opponent's, I'll mistime or mislocate my placement or throw-in.

Actually, my first experience with Go was tsumego problems - very easy ones, only one move needed to be made. They were a small puzzle game on a MUD that I played when I was 13. There was this "go player" mob in one of the rooms, and a copy of the rules for Go (which you could 'get' and 'read'), and from that you were supposed to infer the idea of two eyes. Then you would talk to the player, and he would set up a position on the board, and you would 'suggest' a move to him. Of course you could just guess randomly until you got it, although there were a handful of problems (probably five or so); but I got the idea that way.

Here's a puzzle that occurred to me this morning: eggs in a basket problem. Not really a tsumego problem in the traditional sense, but it should be interesting to work out anyway. I don't have the answer, but it shouldn't be too hard to work out.

Beginner Exercise 12 / Solution last edited by on July 27, 2004 - 18:04
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