Influence

In a rough intuitive understanding, influence is the live stones' radiated "light" towards the outside. Precise models refer to the stones' impact on other intersections.

Definition

A player's live (outside) stones have a greater impact on other intersections the more

• easily friendly stones there can be connected and get life,
• easily the player can make territory there,
• difficult it is for opposing stones there to be connected and get life,
• difficult it is for the opponent to make territory there.

Historical background

Apart from rough intuition modelling influence functions or maps for computer programs, previously reliable definitions of influence appear to have been missing. The "impact model" definition above is given on page 57 of the book Joseki 2 Strategy, which is published in 2011. Page 71 shows a more precise "theoretical model", which replaces "easily" and "difficult" in the definition by formal degrees of connection, life and territory.

Additional remarks

Traditionally influence was considered an outside-only property. However, influence can be considered on the inside, too. Depending on one's application, one might ignore the inside, where useful.

Each stone has a certain influence on the board. Captured stones have an influence close to zero. Surrounded stones that make a live group, influence only the surrounding group. Stones that are in open space have an influence on that open space and the stones bordering that open space. Influence is a long-range effect.

• The stronger a group, the greater its influence on a neighbouring area.
• The more open the neighbouring area, the greater the group's influence.
• The weaker the other groups neighbouring that area, the larger the group's influence.

Examples

9x9  

For example, the central stone has influence in all directions. On a board as small as 9x9, the influence is rather strong towards all parts of the board. Whatever happens in the corners or at the sides will be greatly affected by this stone.

corner  

In this typical outcome of a 3-3 point joseki, White has corner territory, while Black has central influence. The White tails will also affect the sides somewhat, but since they can be easily blocked off, we can say that the sides are more influenced by the black stones which extend farther towards the side.

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See also:

• Thickness, where this page's description is included.
• About influence.
• Non-fiction
• InfluenceMap
• Discussion moved to influence function.
• Geo-Strategic Lessons from Go(shi4) [1] A uniquely Chinese perspective on shi/influence. More and more during the last decade, military and foreign policy thinkers have been realizing that Go may have applicability in both understanding Chinese foreign policy and affecting it. Go has been coupled with shi.
• The Protracted Game: A Wei-ch'i Interpretation of Maoist Revolutionary Strategy (1969) was the seminal work.

One document that attempts to draw broad geo-strategic influence lessons is:

• Learning from the Stones: A Go Approach to Mastering China's Strategic Concept, Shi, by Dr. David Lai: Strategic Studies Institute monograph, 35 pg. ISBN: 1-58487-158-X.