1997-4-16 last update, 1997-2-1 first day
Robert Jasiek, jasiek@snafu.de
Copyright: All rights of the author are preserved according to the international law.

Game End Classification

The main classification of game end rules is done as to their scoring class and usage of game phases. First the classification is described, then rules sets are assigned to the classes and their features are treated. Also see examples.

Game End Rule Classes

1 Primitive

Instead of determining the winner by scoring primitive rules let the first player without an available move lose the game. Such rules omit passes. Games tend to be very long and are so called pass fights. Their final stage consists of suicides respectively attempts to prohibit those of the opponent. They are important in mathematics.

Virtually primitive rules only have an alternation phase with a game end condition.

2 Stone

The simplest scoring method considers

grid points only. Both players fill as many grid points as they can. Only single eye points or small shared spaces remain. The final positions naturally become terminal. To minimize empty grid points it is of great strategical importance to connect own groups.

Stone rules have no stop or confirmation phases. - Sometimes stone rules are also called area rules.

3 Area

Basically area rules score the grid points as

Generally the score of a player is the grid points of his colour plus all empty grid points that are monochromely surrounded by his colour. The scoring allows moves inside own territory that are free of cost. Thus all removals can be solved by actual play.

3.1 Simple Area

Simple area rules have no stop or confirmation phases. The game end consists of two successive passes. The remaining board position is scored in any case.

3.2 Agreement Area

Agreement area rules include stop and confirmation phases. Confirmation is done by mutual agreement of the players. Disagreement results in resumption of the alternation phase and play proceeds as in simple area rules.

4 Territory Rules

Basically territory rules score only empty grid points but add prisoners:

Generally the score of a player is all empty grid points that are monochromely surrounded by his colour plus all prisoners of the other colour (with each prisoner being worth one point).

Since stones on the board are not added to the score, removals are not caused by board plays but left for the confirmation phase.

4.1 Simple Territory

With simple territory rules a confirmation phase is performed as if it were an alternation phase. Removals in the confirmation phase are free of cost due to pass stones.

4.2 Agreement Territory

Agreement territory rules include stop and confirmation phases. Confirmation is done by mutual agreement of the players. Disagreement results in resumption of the alternation phase or in a void game.

4.3 Life-Death Territory

Life-death territory rules include stop and confirmation phases. Confirmation is done due to rules. The rules attempt to describe which stones to remove. Logical definitions are impossible.

Features of Rule Sets

The meanings of the features are: history = evolution, use, predecessors; philosophy = main conceptual intentions of game end rules; exceptions = main special rulings; length = text length of game end rules; counting = advised counting method; shared = counting of empty grid points not monochromely surrounded; eyes = counting of monochromely surrounded empty grid points in seki; komi = advised value of even games; handicap = area compensation points for white if at least two handicap stones; pass = adjustment for passes; equality = equality of area/territory scoring; logic = possibility of mathematical proof / rules treat any board position; void = void game possible; constant = constant game end rule included; procedure = performance of final game phases

1 Primitive

Primitive

2 Stone

Ancient

Ikeda Area I

Greedy Ancient

3.1 Simple Area

Ikeda Area II

Ikeda Area III

Elementary

Tromp-Taylor 1996 [link]

Simple

3.2 Agreement Area

Ing 1974

New Zealand 1978 [link]

Ing 1986

Chinese 1988 [link]

Ing 1991 [link]

AGA 1991 [link]

4.1 Simple Territory

Ikeda Territory I

Ikeda Territory II

4.2 Agreement Territory

IGS

4.3 Life-Death Territory

Japanese 1949

World Amateur Go Championship 1980

Japanese 1989 [link]

WWGo 1996 [link]