Corner moves: hoshi, san-san and an introduction to influence

Remember the proverb mentioned in the article "Playing his first games":

The corner is golden, the edge silver and the centre is a public garden.

Aujourd’hui, nous allons voir deux premiers coups possibles dans un coin : le hoshi et le san-san. Pour chacun d’eux, nous allons développer leur but et une suite de coups possible pour poursuivre dans le coin et sur le bord. Avant de présenter ces deux coups, nous allons voir une notion importante au go : l’influence.

Notion of influence:

Theinfluence is a term often used to refer to a group of stones that radiate or exert force on the entire goban. This group of stones generally faces the center of the goban.

Influence is often the counterpart of territory and in some move sequences, when one player builds territory, the other develops his influence. These two concepts are therefore closely linked.

Example:

In this position, the black group faces the center and upper edge of the goban, while the white group faces the edge. With his group, white has almost safe points, because at the end of the game, black will have trouble reducing the white territory. Black, on the other hand, having a group facing the center, does not make points immediately because its stones do not surround any area. On the other hand, its group of stones exerts a force or influence on the goban. But what is the advantage of such a position?

The influence helps to help your weak groups, to attack the weak groups of your opponent or to facilitate the construction of territories.

It has several functions, that's why it can be advantageous! You will find below for each of these functions an illustrative example (some of them perhaps surprising).

In the case of weak groups to help, we can take as an example a student with a lack of self-confidence. To try to regain self-confidence and thus help this less developed part of himself, he will try to build on his strengths, for example playing the guitar, which is an activity where he feels good. By relying on this strength, he can for example try to play in a music group to regain his self-confidence.

To go, in the same way, influence is a strong point that allows weak groups to turn to it to develop.

Example:

Ici le groupe noir est attaqué par le groupe blanc, notamment par la pierre 1. Il se dirige donc avec la pierre 2 vers le centre, là où le groupe de pierres noires marquées exerce son influence, pour pouvoir s’extraire de l’attaque de blanc.

In the case of weak groups to attack, we can take the more bellicose example of an army A wanting to attack a group of the enemy army B. To facilitate its task, Army A will try to push this group to flee to its own forces, to take it in pliers. This will make it much harder for the small group to retaliate because it will be in a weak position.

Example:

Noir attaque ici le groupe blanc avec 1, 3 et 5 en le poussant vers son influence exercée par le groupe marqué par les croix. Blanc est en position de faiblesse et de plus, noir arrive à agrandir son territoire sur le bord supérieur avec le coup 3 en attaquant blanc.

Finally, in the case of a large territory to be built, we can take the example of a woman who wants to set up a professional project. To this end, she would like to develop a professional activity more in tune with herself. In fact, she lists her potential: her experience as a chemist and her willingness to help the population in need of drinking water. She then thinks of the idea of getting involved, for example, in a project to develop a new material that filters seawater. She has thus developed something that really suits her where she can fully express different facets of herself!

Example:

The marked black stones exert a strong influence on the goban and especially on the upper edge, where black can try to build a large territory. Here if white does nothing, the influence of black can easily turn into territory!

Hoshi:

Hoshi is the name given to the moves played on point 4-4 on the corner. It is a move to the influence that is symmetrical, e.g. it does not favour either of the two adjacent edges.

Pour développer le hoshi sur le bord, noir peut jouer un coup près d’une des croix sur le diagramme ci-dessous. Si blanc veut réduire le potentiel de développement du hoshi sur les bords, il peut jouer sur une de ces croix également. Noir aura alors plus de mal à se développer sur le bord occupé par blanc. Si blanc arrive à jouer sur les deux bords, alors la pierre noire au hoshi aura beaucoup de mal à se développer sur les bords pour former un grand territoire, c’est pourquoi il est intéressant pour noir de jouer dans l’une des deux directions occupées par les croix.

Let's imagine that black is played on one of the crosses. So to prevent it from playing in the direction of the other cross, white can approach the corner of black and form a territory that will prevent black from developing.

Example:

Here black already has a hoshi stone and an extension stone. White approaches the corner with 1, black decides to extend in 2 to consolidate his territory on the upper edge. White enters the black corner with 3 and black defends the corner with 4 to prevent white from penetrating deeper into the corner. White then builds a life base with 5 and takes a position on the right edge.

Such a sequence is called a joseki.

A joseki is a sequence of moves developed by go players that achieves a fair result between black and white.

Above for example, black and white divide the corner equally and each develops a position on one edge.

There are thousands of josekis, many books and collections have been published on this theme. For each joseki, variants exist, which is why it is impossible to know them all. The most important thing when you start to go is to know some of them to have landmarks and develop reflexes. Then, analyzing these josekis is important to understand the involvement and importance of each move and the help of a teacher may be necessary.

San-san:

The Japanese word san means 3, because san-san is the name given to the moves played on point 3-3 on the corner. It is a move to the direct territory, which is also symmetrical. This is the move just below the hoshi on the diagonal of the goban.

To better see why this move is focused on direct territory, let's look at the following joseki:

Here, white approaches the black san-san with move 1, played on the hoshi. Then black grows in 2 to grow a little on the right edge, white extends in 3 to block access to the center of black. Black plays in 4 to expand on the upper edge and white responds in 5 to block access to the black center. Black plays 6 to expand on the right edge, and white still blocks access to the black center with move 7. We see that in this joseki, white wants to confine black in the corner and close off access to the center, and black extends along the edges to build a territory. That's why san-san makes it easy to make territory.

This joseki makes it possible to see the interdependence between influence and territory, because here black only develops its territory while white only develops its influence.

In this article, two important new themes have been introduced in addition to hoshi and san-san:

  • The notion of influence
  • Two joseki

These notions can be difficult to understand at first, which is why I will come back to them in future articles that will deal with them in more depth. I chose to introduce them here because one of the most popular moves nowadays in the area is the hoshi, and it is in my opinion impossible to talk about this stone without introducing the notion of influence. Concerning the josekis, I think that when you start the game of go, they can be interesting to know to have landmarks when you play in the corner.

I hope this article has more for you, feel free to ask me questions or comment on it!

Have a good game 🙂

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