We will talk about two techniques of stone capture, the shicho and the geta. At the end of the article, you will be able to solve some problems allowing you to familiarize yourself with these techniques.
A small clarification for the rest of the article, and for the next articles to appear: the white player and the black player can be designated only by the color of their stones, which are white and black.
Shicho is a Japanese term that can be translated as stairs. The term ladder is also used to refer to the same thing. But why talk about stairs at go game?
Here the marked white stone has only one freedom, symbolized by the cross, so it is in atari. White can therefore play on this cross to save his stone, because in this way, the group of two stones he will form will have two freedoms. Let's see what the black answers in this case:
The black player answers with stone 2, and the white group is again with only one freedom, symbolized by the cross: he is still in atari! He can therefore try to save his stones again by playing on the cross, but black will use the same technique and after 6 moves, both players will find themselves in the following position:
Once again, the white stones are in atari! White can try to save his stones, but maybe you will have understood it, black will use the same technique to keep the group of white stones in atari. If white persists in trying to save his stones and continues over the entire goban, both players will find themselves in the following position:
Despite the magnificent staircase formed by the white stones, black only has to play on the intersection marked by a square to capture the entire group of white stones! In fact, white should not have tried to save his stone from the beginning, because it was going to be captured in a form of stairs, or shicho.
A shicho is a capture technique that keeps the targeted stones in atari.
In the previous example, we see that if white tried to save his group of stones, it would take the form of a staircase following a diagonal of the goban. What happens if a white stone is placed on the path?
Here, the presence of the marked white stone will change the situation. Let's see this time what happens if white decides to save his stone taken in the black form.
After the above sequence, the white stones are saved with the white stone marked ! This stone is called a shicho breaker, or ladder breaker in English, because it stops the shicho and saves the group of white stones attacked.
Depending on the rest of the goban, therefore, a stone taken in a shicho can be saved or captured. To distinguish the case in which we find ourselves, it is necessary to visualize in his head the sequence of blows that will follow if you try to save (or capture) this stone. We call it "reading" the sequence of blows. To work on your reading skills, it is best to try to visualize during exercises or real games in his head the probable sequences of moves.
Geta is a Japanese term that can be translated as a net. As its name suggests:
Geta is a technique used to capture stones by locking them in a "net".
The marked white stone is here trapped in the net, or geta, erected by black. Although it is now only a freedom, it cannot escape and is therefore captured. Let's see if white is trying to save his stone:
He pushes in 1, but black plays 2. Then if white pushes back in 3, black only has to play on the marked intersection to capture the three white stones, because they are in atari. So, the white stone was beautiful and well trapped! Let's look at another example of geta:
Here again, the two marked white stones are trapped in the black geta. Even if these two white stones have three freedoms, they cannot escape. You can check yourself in the exercise at the end of the article if you have understood why.
Here is one last example of geta, more complex this time:
In this example, the three marked white stones seem to be able to escape. However, thanks to the presence of the black stone, they are indeed captured. You can discover why through this interactive explanation:
This example, rich in variation, clearly shows the strength of geta in certain situations. Because to work, a geta depends only on the local position in which it is, while for a shicho, the global position of the goban and especially on the path of the shicho must be favorable. That is why, when it is possible, it is better to use a geta rather than a shicho when capturing stones.
Here are now 8 exercises to familiarize yourself with shicho and geta:
I hope you licked it!