Lesson 119 : Salvation From Outside (1)
Lesson 119 : Salvation From Outside (1)
It is said that one of the difficulties in writing a Baduk-playing computer program is determining the boundary in which it searches for the candidate moves.
In order to do this, the program should be able to differ what is its own force and what is not, what is related and what is not, and what is inside and what is outside, etc.
The reason that a computer should know these things is so that a sea of unlimited moves does not haunt it.
The program will be designed to deliberate only inside of the boundary.
However, sometimes, good moves can be found outside of the situation at hand. Until now, as far as I know, finding this kind of move is only possible for a human being.
Diagram 1
White just covered the six black stones with 1.
Since six stones are too many to give up, Black has to save them, but how?
Diagram 2
Obviously Black cannot save the group if he tries to find an optimal move inside the situation.
As shown here, Black 1 and 3 are impotent attempts to escape, that are easily blocked by White 2 and 4.
Diagram 3
To go out with 1 and 3 is not a solution either.
After being cut by White 4, Black cannot fight against White since the five black stones separated on the side have only a few liberties.
Diagram 4
As you might have expected, Black 1, which seems to be placed outside the current situation, is an excellent move to save the six stones.
If White plays A, Black will connect under with B.
Diagram 5
If White blocks with 2, Black 3 and 5 will be good moves.
Because of the exchange of Black 1 and White 2, White cannot but go out with A instead of cutting at B, and Black succeeds in escaping.
Diagram 6-1
The black group here cannot live inside, since the space is too narrow.
If he plays A, then White will kill him with B, and if he plays C, then White, D. However, if Black depends not only on the shape of his own group but also the situation he is in, he can save the group.
Diagram 6-2
For White, to connect at 1 is the best possible choice.
Of course, Black can still live with the sequence up to 8, but White can capture the three black stones in sente anyway.
If White plays elsewhere with 3, Black will cut there and then White will lose far more than just letting Black live in gote.
Because White has to defend the cutting point at 3, Black C in the previous diagram can be a sente.
Please verify it by yourself.
Diagram 7
The core move is Black 1. After it is played, the rest becomes quite easy.
If White gives atari to it, Black should come down with 3.
Then, it is apparent that White A doesn’t work because Black can easily live by playing C in sente.
Moreover, White B doesn’t work because Black C is a sente anyway, which I’ll explain later.
The writer is a baduk professor at Myongji University and a professional player of the game.