# Kee Rules of Go / v3.0

Sub-page of KeeRulesOfGo

## KEY FEATURES OF KEE RULES v3.0

### 1. Superko rule

Basically situational superko (Rule A.4).

The difference is a pass of a player can erase her own previous board situations. If not, some bestiary may occur. (See Go Rules Bestiary)

### 2. Ending determination

Game situation repeats.

The rationale is that a perfect player would play in the same way in front of the same game situation within the framework of Kee Rules. This makes the next game situation also repeats. Inductively the same chain of game flow will repeat forever.

### 3. Scoring

One breakthrough of Kee Rules is that it allows multi-board position scoring.[1] When a game ends cyclically, there is no reason to say any board position is superior to others for scoring. Actually if a player passes there are two possibilities:

(a) She is satisfied with the board position; or

(b) She is forced to do so - Superko rule prohibits her from further move.

On the other hand, if she places a stone in her turn, it means that she is unsatisfied about the current board position. Therefore, scoring passed board positions is in fact a fair and natural treatment. This breakthrough is apparent in some board shapes, like 2x1, 2x2 and 2x3.

### 4. Suicide

Kee Rule is silent about suicide. Personally I prefer no suicide as it has nothing to do but just a ko threat.

### 5. Board shapes

Kee Rule is written to cater as many board shapes as possible. Non-rectangular or higher dimensional, you name it.

### 6. Number of players

Kee Rule is written to cater more players too. You will find it as natural if you read it with 3 players or more in your mind.

### 7. So...

I believe Kee Rules can serve as the basic principles for computer programming and go rule unification in the future. Any comments are much appreciated.

By the way, could anybody teach me how I can try my rules in computers?

## KEE RULES OF GO

(Version 3.0)

### A. STARTING A GAME

1. Players, each possessing unlimited stones in her own color, plays on a grid of intersections.

2. Conventionally, the colors are black and white with black playing first.

3. In each turn, the player can choose to place her stone on an intersection, or pass. However;

4. A player cannot place a stone to produce a board position that already exists in her board history. (For more details about board position and board history, please refer to Rule C.1)

5. Some rule sets prohibits suicide, i.e. placing a stone which causes death to none of its adjacent opponent groups but its own group. (The definition of dead groups can be found in Rule B.2)

After a stone is placed:

1. Each single stone or each set of adjacent stones in the same color forms a group.

2. A group is dead if it is not adjacent to any unoccupied intersection.

3. All dead opponent groups are removed from the board. The suicide group is also removed from the board if applicable.

### C. UPDATING BOARD HISTORY

After a player has taken a turn and the dead stones are removed:

1. The board position, which comprises the information of which intersections occupied by whom, is checked against Rule 4 in Section A. If allowed, it is added to her board history.

2. If the turn was a pass, her board history is emptied before adding the board position to it.

3. The game situation, which comprises:

(a) the player who then takes the turn;

(b) the current board position; and

(c) the board history of each player,

is then recorded.

### D. ENDING A GAME

1. The game ends when the game situation repeats.

### E. SCORING

1. A board position is satisfactory to a player if it has been passed by her after the first occurrence of the repeated game situation.

2. For each board position satisfactory to a player:

(a) Each single unoccupied intersection or each set of adjacent unoccupied intersections forms a zone.

(b) An intersection is worth one point (zero otherwise) to her if it is occupied by her, or it is unoccupied but all intersections adjacent to its zone are occupied by her.

3. The score of a player is the maximum points she can get among all satisfactory board positions.

4. Players can go straight to scoring before the game ends if the satisfactory board positions to each player are generally accepted.

5. The player having the highest score is the winner.

Last updated by Wilton Kee on 9-Apr-2004.

### Discussions

All discussions in the first version are deleted as they are no longer valid in this latest version.

[1]

Bill: Maybe I do not understand, but I do not see the breakthrough. See Ing rules, Spight rules, and Yasunaga's ''constitution'' (I think it was called).

The key difference about scoring is the use of "multi-board position scoring". To clarify:

In all the rules you mentioned, only one board position, which is given by two to four consecutive passes, is used to calculate the score.

In Kee Rules, for each player, there is a corresponding set of passed board positions for calculating the score. The score is just the maximum from the set.

Why it makes the difference? Let me illustrate in a 2x2 go board:

2x2 go board

aggressively takes a step to strike for a possible win.

White 6 passes

responds by taking the two black stones. Black throws a stone back to the board. White still thinks that this board position is good for her as she has one more point there, so she passes.

Black 9 passes

responds by taking the two white stones. White throws a stone back to the board. Black still thinks that this board position is good for her as she has one more point there, so she passes.

White 3 passes

( in the diagram) responds by taking the two black stones. Black throws a stone back to the board. White still thinks that this board position is good for her as she has one more point there, so she passes.

Black 6 passes

responds by taking the two white stones. White throws a stone back to the board. Black still thinks that this board position is good for her as she has one more point there, so she passes.

It is getting too boring. However from the above pattern we would expect similar oscilliation to continue under Kee Rules until the game situation really repeats.

As game situation would repeat somewhere with 2 black + 1 white or 1 black + 2 white, under all other rules, black or white would win by one point. But it violates our common sense. Just a fair oscilliation cannot imply either side to win.

However, in Kee Rules, Black would use 2 black + 1 white to calculate the score, while White would use 1 black + 2 white to calculate the score. This gives each side two points and it is a draw.

This is the breakthrough.

Bill: Thank you, Wilton. :-)

Just a note. Under my rules the 2x2 is a seki with correct play.

Wait a second. I think that you overlooked a repetition of the situation. In your sequence, when takes the two Black stones, it repeats the situation after .

Well, after , the "board position" repeats, but not the "game situation". If you look carefully at the history of board positions of both sides, you will find that the history of is different from the history of . For example, the following board position is in Black's history after , but not :

Black's history

Using repetition of "game situation" instead of "board position" to end the game might get the rules a bit more complicated. However, this is the only way we can ensure same response of a perfect player. Imagine facing the same board position but with different prohibited moves in the future, a perfect player might make a different choice. That is why the same board position does not guarantee the exhaustion of variations.

Bill: So your game situation is more specific than the usual situation in reference to situational superko. The latter only specifies the whole board position and player with the move.

Could you please kindly show me how a seki comes out in Spight Rules?

Bill: See Spight Rules. :-)

Kee Rules of Go / v3.0 last edited by 61.10.7.202 on April 17, 2004 - 10:17