Back to my home | Notes and study | Magyar szöveg
You can find my initial post on Usenet
here (or the whole thread,
here). It contains background information and details in order to understand
my goals in creating this ruleset.
The essence for the impatient: area scoring, no superko, finite stone supply, modified ko in continuations.
Basically, I intended to create a Chinese style (area with draw on repetition) ruleset which doesn't use superko and produces the traditional rulings for moonshine life, send2-return1 and true cycles like triple ko or eternal life - but it is logical and simple at the same time, without relying on exceptional rulings and precedents like the official Chinese rules. For completeness, I also include territory scoring rules based on the same ideas, besides the primary area version.
At the moment, these rules are highly experimental (especially the territory scoring version). The text will likely change. In wording and structure my aim is to create a text that is easy to read.
The current text is V1.5. Significant changes are listed at the bottom.
The game is played by two players on a grid composed of an arbitrary number of vertical and horizontal lines. (The usual size is 19*19, with 9*9 or 13*13 used for short games.)
The board is initially empty. The game is started by black. The players move alternately. During a move a player places a stone of his own color on an empty intersection of the board. Placing a stone is no obligation, a pass is also a legal move.
Adjacent stones of the same color form a string. The empty intersections adjacent to a string are the liberties of the string. When a string has no liberties, it is captured by the opponent and taken off the board as prisoners. After each stone is played enemy stones are checked first, friendly stones second.
Intersections are considered adjacent if they are vertically or horizontally next to each other.
Capturing a single stone in a way that the new stone doesn't immediately become part of a bigger string and has only one libery (ie. it is in a recapturable state) is a ko capture. The opponent cannot immediately recapture, placing a stone back to where his original stone was captured from.
The players have a finite supply of stones. In practice, if the prisoner difference exceeds a given limit (specified by the tournament rules), the player who lost more stones is considered to have "run out of stones" and can only pass.
This rule has usually no effect, it is only necessary to prevent certain kinds of abuses. A suitable value for the limit can be half the number of intersections of the board (or the complete size, for smaller boards). For example 180 stones on a usual 19*19 board.
The aim of the game is to achieve a position where neither player places additional stones, and where the friendly stones control bigger part of the board than the enemy stones, measured by the score.
The game ends in one of the following ways:
Tournament rules may specify a different number and may grant this right of claiming a draw based on repetition to third parties such as referees as well.
When both players pass in succession, the game stops. Either player can demand the continuation (resumption) of a stopped game (with normal move order). The maximum number of possible continuations is limited by the tournament rules.
It is advisable not to make this limit too low, so that it doesn't ever interfere with normal playing out of disputes.
The position is final and the game ends and is scored when neither player demands resumption or this above limit is reached.
When a continuation of a stopped game is started either player can demand it to be played with slightly modified ko rules as follows.
Before recapturing a ko a player can optionally pass for that specific ko capture ("challenge the ko"). Later, if he eventually succeeds in playing the prepared ko capture (ie. the opponent could not or did not use this extra opportunity to win the ko), the opponent can not recapture in the same ko (nor challenge it) until a regular pass of either player intervenes (which clears the lock).
Ko-challenging passes are not considered regular passes for game stops. A player can only play a ko-challenging pass for a ko capture on which he haven't already prepared a lock. A player can not play a ko-challenging pass for a ko capture that is prohibited by the normal ko rule at the moment (ie. the last opposing move was a ko capture in that ko).
This last restriction may be unnecessary and will probably be removed.
A ko capture is considered to be "in the same ko" as an earlier ko capture of either player if it affects the same two intersections and if the configuration of the stones on the surrounding directly adjacent 3-6 intersections did never change in the meantime. A ko capture is considered to be a ko recapture if it is in a ko in which the opponent already captured earlier in the same continuation.
For simplification, tournament rules may ignore this rule. In this case, the players have no options to capture traditionally dead groups with virtual kos (eg. moonshine life is alive).
In a stopped position, stones which both players consider to be obviously capturable by further play are dead, other stones are alive.
In a stopped position, a player's territory consists of intersections that are empty or occupied by a dead stone of the opponent, and are surrounded by him.
A set of intersections is surrounded by a player if they are only adjacent to each other and (one or more) alive stones of the player.
A player's score is the number of intersections under his control, that is, either occupied by his alive stones or within his territory.
Tournament rules often restrict those first moves to fixed patterns.
Actually the true handicap is one stone less than the number of B stones (with komi), or half stone less (without komi).
The territory scoring version is motivated by the fact that superko-free territory rules (Japanese style) use a flawed pass-for-ko hack and therefore have to rely on exceptional rulings for moonshine life, and my ko rules may be an interesting alternative to pass-for-ko. It is not meant to replace or to be compatible with traditional Japanese rules, because of dropping the concept of locality, allowing almost unrestricted ko fights even in confirmation (also dropped are seki and no suicide).
There is no intention to make a game with territory scoring end with
exactly the same score difference as with area scoring.
When used in territory scoring, the followings override the earlier clauses, accordingly.
A player's score is the number of intersections in his territory, plus the number of opposing stones captured, plus the number of dead stones in his territory.
A confirmation sequence is a special continuation that is not part of the game, it is only used to verify a claim. It starts from a disputed position, and stops when both players pass in succession (this new position is examined, then the original position is restored). The players can make the following claims:
Tournament rules are advised to have sufficient limits for the maximum number of claims and the maximum number of confirmation sequences allowed for a claim.
Have been moved to the study page,
I'll only repeat a single example - capturing moonshine life:
1.bA4 2.wPass (necessary because the corner ko capture is not a legal
move now; could also make a meaningless board play or capture in the double
ko) 3.bPass (game stops but W requests continuation) 4.wA3 (trying it
directly first) 5.bH1 6.wK4 7.bA4 8.wG1 (again the corner ko is not legal,
this time W better avoids the stop) 9.bK3 10.wPassA3 (legal now) 11.bPassH1
(trying to mess things up) 12.wPassK4 (just to be on the safe side) 13.bH1
(locking) 14.wK4 (locking) 15.bPass (no legal ko captures, therefore no
legal pass for lock either) 16.wA3 (locking) 17.bK3 (trying another lock is
no better) 18.wG1 19.bPass (no other move) 20.wA1
Created: 2003 Oct 17 Updated: 2004 Jul 24