KeeRulesOfGo/ v4.0

Sub-page of KeeRulesOfGo

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2x2 go board
2x3 go board
2x1 go board
P1, W's turn
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KEE RULES OF GO v4.0

You may be interested in its key features first[1].

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;

(a) A player cannot place a stone to produce a board position which exists in her temporary history; and

(b) A player cannot place a stone, or even pass, to produce a board position which exists in her permanent history.

For more details about board position and history, please refer to Rule C.

4. 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)

B. REMOVING DEAD STONES

After a stone is placed by a player:

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 suicidal group is also removed from the board if applicable.

C. UPDATING BOARD HISTORY

After a turn of a player with the dead stones are removed:

1. The board position, which comprises the information of which intersections occupied by whom, is checked against Rule A.3.

2. If Rule A.3 is satisfied, the board position is added to her temporary history.

3. If the turn was a pass, her temporary history is reset to include only the current board position.

4. If a stone of a player is removed before she places the next stone, all board positions produced by the stones of its group are added to her permanent history.

D. ENDING A GAME

1. A player loses when she has no legal play.

2. The game ends when all players with legal plays choose to pass in two consecutive rounds.

3. Players can go straight to scoring before the game ends if they can conclude the final board position.

E. SCORING

1. On the final board position:

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

(b) A player gets one point from an intersection if it is occupied by her, or it is unoccupied but all intersections adjacent to its zone are occupied by her.

2. A player is ranked lower if she loses more quickly, and ranked higher if she gets more points.

Last updated by Wilton Kee on 17-Apr-2004.


[1]

KEY FEATURES

1. Superko rule

I would describe Rule A.3 as a discriminating situational superko (DSSK).

If a player placed a stone at an intersection which is immediately removed by her opponent, it might indicate that she is just prolonging the game. It is quite disturbing actually. DSSK is not meant to forbid such disturbing moves, as sometimes it can be a tactical technique. The problem actually arises when such thing happens repeatedly.

Therefore, board positions are classified as two types - disturbing and non-disturbing. Passing can erase only non-disturbing previous board situation, but not both. The idea of using passing to remove ko ban is introduced by Spight[1001] - if passing is not allowed, some bestiary may occur. I just wish to add a point, if passing is a full remedy to ko ban, some games may end when players are still placing stones (Isn’t it annoying?).

What can be said as a disturbing move? The following are examples:

[Diagram]

2x2 go board

B3 is the disturbing move as White would respond at a.

[Diagram]

2x3 go board

B5 is the disturbing move as White would respond at b.

[Diagram]

2x1 go board

Well, in this tiny board, even the first play can be disturbing.


2. Ending determination

It cannot be simpler - making sure everyone has nothing to say on such final board position. 2N consecutive passes is necessary to N-player games, ko ban might still applies before the first pass of a player.

3. Scoring

In Kee Rules, some players may lose before the game ends just because she has no legal play (can’t even pass!). Actually this only applies to disturbing players. Normal players would eventually pass on a final board position.

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?


Discussions

Wilton Kee:

You may find Kee Rules of Go v3.0 here. It is a completely different rule set in which the ideas of multi-board scoring and ending determination by game situation are introduced.


I have tried Kee Rules v4.0 for several small boards and the best first plays with their corresponding results are listed below. I only worked it out by my hands, so please point it out if there is any mistakes:

1x1: Pass (draw)

1x2: Pass (draw)

1x3: 1-2 (+3)

1x4: 1-2 (+4)

1x5: Pass, 1-1, 1-2, 1-3 (draw)

1x6: 1-2 (+1)

1x7: 1-2 (+2)

1x8: 1-2 (+3)

1x9: Pass, 1-2, 1-4 (draw)

2x2: 1-1, Pass (draw)

2x3: 1-2, Pass (draw)

2x4: 1-2 (+8)

2x5: 1-3 (+10)

3x3: 2-2 (+9)

3x4: 2-2 (+4)

3x5: 2-3 (+15)

4x4: 2-2 (+2)

4x5: 2-3 (+20)

5x5: 3-3 (+25)


Just feel free to add your comments about Kee Rules v4.0 below.


Robert Pauli: Please explain me/us

4. If a stone of a player is removed before she places the next stone, all board positions produced by the stones of its group are added to her permanent history.

I'm neither sure what positions are added, nor exactly when this has to happen (after each capture?).

Wilton Kee:

Let us look at the 2x3 board in KEY FEATURES.

B5 was removed by W6 (before Black placed the next stone). Therefore, the board position produced by B5 (with 3 black stones on upper row and 2 white stones on lower row) was then added to Black's permanent history.

Furthermore, since B1 and B3 belong to the same group of B5, the board position produced by B1 and B3 were also added to Black's permanent history.

Not all captures lead to a board position adding to permanent history. Normally stones captured are not "just freshly" placed. If it is not fresh, no board positions are added to permanent history. This rule aims at prohibiting repeating disturbing moves.

Robert Pauli: Thanks, guess I got it:

If a player's youngest stone gets captured, it and each stone connected to it enters that position into the player's permanent history in which it was the (game's) youngest stone.

However, I don't see how you accomplish to stop disturbing play? For example:

[Diagram]

P1, W's turn



Black's temporary history only holds P1. Other histories are empty. White starts:

 P1  oo..  ..xx   (= 2nd row + 3rd row)
 P2  ooo.  ..xx
 P3  ooo.  .xxx
 P4  oooo  .x..
 P5  ..oo  xx..
 P6  .ooo  xx..
 P7  .ooo  xxx.
 P8  oooo  ..x.
 P9  oo..  ..xx

Both permanent histories still are empty, since no capture took the youngest stone. Each odd position is in Black's temporary history and each even one in White's, since no pass trimmed either. Since P9 repeats P1 in Black's temporary history, Black's capture in P8 was illegal.

But, isn't White disturbing?
Are you intentionally treating this as "ko"?

Wilton Kee:

White is not disturbing and it is a ko.

We would consider a series of moves (say White starts) to be disturbing if it does not contribute any advantage to White when ONLY temporary ko rule applies. The above 2x3 is an example.

However, for this case, White would win the temporary ko if it starts first (lose if Black plays first). There is an obvious advantage to White and so it is not a disturbing move.

Robert Pauli:

To me White is disturbing in the sense that if only the primitive normal ko rule is in use, to no effect here, White has no chance to get Black nor is White forced to defend.

It seems that you only consider cycles to disturb the one that can afford to pass. Correct?

By the way, is putting up v5.0 discarding v4.0 ?

Wilton Kee:

The purpose of permanent ko is to prohibit disturbing cycles that can survive when passing is used as ko threat.

I believe v5.0 is nearer to the ideal rule. But as long as everything is not final, I decide to temporarily keep older versions here for reader's comparison?

Anyway, thank you very much for your comment.


[1001]

Bill: The first to suggest lifting a ko ban after a pass seems to have been Yasunaga Hajime, early in the 20th century.


This is a copy of the living page "KeeRulesOfGo/ v4.0" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.
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