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Dieter's ideas on Go Theory
Path: PleaseReviewMe   · Prev: ElementaryMoves   · Next: UpAndDown
    Keywords: Theory

This page is a personal project by Dieter. It is an attempt to accurately describe Go theory. Go Theory starts with rules. From the rules we can derive principles. For a deeper understanding of those principles, we develop several concepts?. The principles and the related concepts finally give rise to guidelines, or as they are called in Go theory, proverbs. The game has three aspects: technique, tactics and strategy, so proverbs will typically look at one of those three aspects.

I'd appreciate both contentual remarks below and linguistic improvements throughout.

Rules (R)

  1. The rule of capture
  2. The rule of scoring
  3. The rule of alternating play
  4. The rule of ko.

Principles (P)

  1. The principle of efficiency
  2. The principle of flexibility
  3. The principle of liberties
  4. The principle of two eyes
  5. The principle of connection
  6. The principle of development

The principle of efficiency

From R2 and R3 we can derive a meta-principle, namely that you should place your stones with a maximal effect.

Stones should be placed with maximum efficiency

The principle of flexibility

Go is a game of complete information, but it is far from being solved. Some board positions, however, are already solvable by the mind (killing large groups, endgame). In these situations, the player who sees a sequence giving him undisputed victory, will play out this sequence. This can be called "settling the shape". If settling the shape does NOT give a definite advantage, then it gives more information to both players. In particular, when the shape is settled with one move, the opponent is the first to adopt a way of playing that takes the settled shape into account.

Therefor, as long as it is unclear who is favoured by the board position, both players will keep their options open as much as possible. This applies also to part of the board.

(i) Preserve flexibility as long as the position is unclear
(ii) Settle the shape when the position favours you

The principle of flexibility comes from general principles of gamesmanship and the rule of alternating play.

The principle of liberties

From R1 we deduce that liberties are important.

(i) Increase the liberties of your own stones
(ii) Decrease the liberties of your opponent's stones
(iii) Avoid decreasing your own liberties
(iv) Avoid increasing the opponent's liberties

counting liberties forms the basis of the theory of capturing races.

The principle of two eyes

From R1 we also derive the second principle,

A group with two eyes is alive

which forms the basis of the theory of life and death.

The principle of connection

From P1, P2 and P3, we deduce that it is interesting to connect groups, for less stones are then needed to make them alive and the sum of the liberties of both groups will be all the greater.

(i) Connect your own stones
(ii) Cut your opponent's stones
(iii) Don't let your groups be sealed in
(iv) Seal in the opponent's groups

The principle of development

Increasing liberties (P2), establishing a connection (P4), surround empty points (R2) and creating space to make eyes (P3) are all some kind of development. We can also adhere a sense of direction? to the concept of development. We can thus state the principle:

(i) Develop your stones. Choose the best direction.
(ii) Reduce the possibilities for development of the opponent's stones. Force his development to go in an uninteresting direction.

Concepts (C) and proverbs

From the above six principles we can now derive the rest of Go theory, conventionally expressed through proverbs. This includes technique, tactics - which boils down to life and death and capturing races - and strategy. Throughout this development, several concepts? (C) will be defined.

Technique (T)

  1. Ladder technique. From P3 and P5.
  2. Net technique. From P3 and P5.
  3. Nets are better than ladders. From P1.
  4. Extend from atari, if increasing liberties is possible. From P3 and P5.
  5. Hane against the contact play. From P2 and P4.
  6. Block the push through. From P3 and P5.
  7. Block the diagonal. From P3 and P6.
  8. Extend from a diagonal contact play. From P3 and P6.
  9. Connect against the peep. From P5.
  10. Hane at the head. From P3 and P6.
  11. Stretch from a bump. From P3 and P6.
  12. Extend from a crosscut in the absence of neighbouring stones. From P3, P5 and P6.

Tactics

  • The theory of life and death forms an independent chapter which has been abundantly described. The positions called seki can be explained through the principle of liberties, much like the principle of two eyes.
  • The theory of liberties and capturing races has been documented by Richard Hunter.

Strategy (S)

A first strategic proverb, which is also applicable to technique and tactics, is derived from R3 :

S0 The enemy's key point is yours (from R3)

From the principle of flexibility (P6) we get a first concept:

C1The concept of miai : Look for moves that leave equivalent options.

The key concept in strategy is the balance of territory and thickness, which is guided by the principles of efficiency (P1) and development (P5). Another way to look at this balance is the meaning of stones and urgent versus big moves.

C2 Thickness: a group of stones which is firmly connected (P4) and which has sufficient eyespace (P3).

C3 Territory: an area which is surrounded (P4: no cut possible) by a thick group, and in which the opponent has almost no chance to create a lving group (P3).

The usual size of the board, together with these two concepts, gives rise to the following proverbs:

S1 The third line is the line of territory
S2 The fourth line is the line of influence

Hence,

S3 Gladly accept fourth line territory
S4 Third line to stabilize, fourth line to build

The meaning of stones or urgency (U)

U1 Stones that cut apart groups which are not yet thick (C2) are called cutting stones. Those stones are important, from P4 and P1. If those stones are not yet thick, strengthening them is urgent.
U2 Stones that cover a large area are important too, from C3. If those stones are not yet thick, strengthening them is urgent.
U3 Stones that are close to the opponent's thickness, have little room for development (P5). Those are not important. Defending them is not urgent.
U4 Stones that are close to your own thickness also have little room for development (P5). They too are not important. Defending them is not urgent.

The meaning of areas or size (bigness) (B)

B1 Open areas, with a lot of room for development, are big.(P5)
B2 Areas close to own thickness, are uninteresting, because playing there is not efficient (P1).
B3 Areas close to opponent thickness, are uninteresting (B2 and AP1)

We can summarize the meaning of stones and areas in the following strategic principles:

S5 Capture the cutting stones (U1). Corollary: cut the side you don't want (AP1)
S6 Strengthen groups that occupy a large area (U2)
(actually, there is no conventional proverb like this, probably because the instinct of defending territory is strong enough already)[1]
S7 Sacrifice unimportant stones (U3, U4). Corollary: resist capturing unimportant stones (AP1)
S8 Play away from thickness (U3, U4, B2, B3)
S9 As we can see from C2 and C3, territory exists only by virtue of thickness. Hence Play urgent moves before big moves
S10 When there is little urgency, play a move in open space (S8 and B1).

S11 Don't build influence in the direction of stable positions (P1, P5, C2)
S12 Build box shaped territories (P1, C2)
S13 First corners then sides then center (P1, P2)
S14 Approach from the wider side (P5, B1)
S15 Block on the wider side (P5, B1)

More concepts

C4 Aji is the future potential of a position (stones) which is (are) temporarily lost. Bad aji gives more options (P6) to the player who locally has lost (stones).

C5 Stones are light when they have a lot of flexibility (P6). Heavy is the opposite. Mostly, if light stones will be captured, it will be small

C6 Shape is a characteristic of a number of stones. Determining principles are efficiency (P1) and flexibility (P6). Objectives are eyespace (P3) and connection (P4), leading to thickness (C2) and territory (C3).

The study of the different shapes can be done independently. A static treatise on shape is a first attempt. It relies a .o. on the liberties stones ratio for efficiency. Subsets of good shape are good shape. Extensions of bad shape are bad shape.

C7 Forcing moves are moves that force the opponent to settle the shape and reduce flexibility (P6) so that the forcing player can next play according to his opponent's choice.

More technical proverbs

T13 Capture the ladder as soon as possible. (P6)
T14 Don't try to cut the one-point jump unless it gives a clear advantage (P2, P6)
T15 Don't cut knight's moves unless it gives a clear advantage (P2, P6)
T16 Don't peep where you can cut (P4, P6)

Finally, I need a stronger explanation than the ones I have available for the idea that playing close to (strong) stones in strengthens both sides. This is the basis for the theory of leaning attacks and sabaki techniques. It also explains why to attack from a distance. Proverbs yet to be included:

Reducing techniques

  1. Knight's move against capping play from the third line (3rd line and 4th line significance)
  2. One space extension against capping play from the fourth line (3rd line and 4th line significance)
  3. Reduce a framework by playing on the sector line (from attacking techiques and connection principle)

Attack and defense techniques

  1. Attack from a distance (that's a tough one, because it mixes technique)
  2. Make a base first, then jump to the center (eyespace over connection ??)
  3. Knight's move to attack (development)
  4. One space jump to defend (no clue, lightness and shape maybe)
  5. Two space jump to sacrifice (lightness)

Cutting and connecting principles

  1. Avoid connecting along dame warning (efficiency)

Your comments are highly appreciated.

Dieter


Deshi comments

[1] Charles I'm not aware of any principle exactly covering this point. But see make both ends strong.



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This is a copy of the living page "Dieter's ideas on Go Theory" at Sensei's Library.
(OC) 2003 the Authors, published under the OpenContent License V1.0.