KataGo planned rules - drafted

[luigi]

Playing around with it - how about this? It's certainly not a normal sending-two-returning-one (the third move isn't even a capture!), but it is a sequence of moves that does the 3-cycle repeat. I should or shouldn't be prohibiting this one too?

$$Bc
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$$ | . . X O . X O . . . .
$$ | . . X X O O O . . . .
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Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X O . X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
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$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

$$Bc
$$ ----------------------
$$ | . . X O 1 X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
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$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X O 1 X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

$$Bc
$$ ----------------------
$$ | . . X 2 X X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X 2 X X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

$$Bc
$$ ----------------------
$$ | . . X O . 3 O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X O . 3 O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

I'm not sure if there are other cases to also be found. Categorizing/proving all the cases seems a little fiddly.

Thankfully, nobody in real life probably wants to play this sequence, so maybe it doesn't matter if this one also gets prohibited too.
(Now watch as someone now posts a rules beast where doing this sort of sequence is correct...).

The way I see it, if the ko rule forbids repeating the position that existed one play ago, the Chinese superko rule forbids repeating the position that existed two plays ago, and I assume the player to move is not included in the idea of position (since the rule used to be misinterpreted in the West as describing positional superko).

In other words, in your diagram would be allowed, as it doesn't repeat any position. If White then passes (a pass is not a play), to the left of would be forbidden, as it repeats the position after .

[moha]

if the ko rule forbids repeating the position that existed one play ago, the Chinese superko rule forbids repeating the position that existed two plays ago

I'm not sure where this idea comes from, but is almost certainly wrong. Chinese ko rules forbid a player to prevent game end with any cycle where the stones lost is not symmetrical, regardless of the length of that cycle. Consider a sending-two-returning-one with a double ko seki, for example.

One common approach in computer go is that cycles (that are not forbidden by the normal ko rule) end the game with a draw, loss or win depending on the stones lost in them. Which is not perfect but may be considered sufficient.

[Bill Spight]

Bill, that one wasn't about scoring a position or Japanese rules. That was about maybe adding "Chinese superko", which would apply at *all* times during normal play, scorable or not, to implement *Chinese* rules.

OIC. As Emily Litella says, Nevermind.

[luigi]

if the ko rule forbids repeating the position that existed one play ago, the Chinese superko rule forbids repeating the position that existed two plays ago

I'm not sure where this idea comes from, but is almost certainly wrong. Chinese ko rules forbid a player to prevent game end with any cycle where the stones lost is not symmetrical, regardless of the length of that cycle. Consider a sending-two-returning-one with a double ko seki, for example.

That's not my understanding, see Chinese superko at Sensei's Library.

[moha]

That paragraph is even rougher than the official texts, which show the simplest case and states a clear intent to generalize. It also works the other way: superko is mentioned, forbidding all repetition, then triple ko and a few other valid cycles are cited as possible exceptions with draw result. No referee would declare draw for an unbalanced cycle.

[Bill Spight]

That paragraph is even rougher than the official texts, which show the simplest case and states a clear intent to generalize. It also works the other way: superko is mentioned, forbidding all repetition, then triple ko and a few other valid cycles are cited as possible exceptions with draw result. No referee would declare draw for an unbalanced cycle.

Yes. The official text certainly seems to be a positional superko rule. In particular there is no mention of sending two returning one, or the like.

　　第六条 禁止全局同形再现

Aside from eyeballing this I ran it through various online translation sites. Google gave this in clear, but technical English.

Prohibition of global isomorphic reproduction.

Several years ago I saw a version that mentioned that a referee might declare no result, despite the text. It may have been back in the 90s, though. I would not trust anyone who said that the intention of the rule was different from the plain text, when it is so short and clear. It may be that top Chinese players do not like the positional superko rule, and so referees defer to them.

[Bill Spight]

Playing around with it - how about this? It's certainly not a normal sending-two-returning-one (the third move isn't even a capture!), but it is a sequence of moves that does the 3-cycle repeat. I should or shouldn't be prohibiting this one too?

$$Bc
$$ ----------------------
$$ | . . X O . X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X O . X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

$$Bc
$$ ----------------------
$$ | . . X O 1 X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X O 1 X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

$$Bc
$$ ----------------------
$$ | . . X 2 X X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X 2 X X O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

$$Bc
$$ ----------------------
$$ | . . X O . 3 O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ----------------------
$$ | . . X O . 3 O . . . .
$$ | . . X X O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

Maybe we could call this Taking one, losing three.

[moha]

In particular there is no mention of sending two returning one, or the like.

The widely circulating old English version does show it as an example for this particular issue, and its phrasing gives useful hints about the real intent (just like where triple ko and similar cycles are mentioned).

It may be that top Chinese players do not like the positional superko rule, and so referees defer to them.

I think the text simply has a hard time explaining actual practice. These positions are rare but still frequent enough to have a decent number of precedents in pro games, maybe even dating back before written rules.

[lightvector]

In other words, in your diagram would be allowed, as it doesn't repeat any position.

Look again. It *does* repeat the position at the start.

[lightvector]

In particular there is no mention of sending two returning one, or the like.

The widely circulating old English version does show it as an example for this particular issue, and its phrasing gives useful hints about the real intent (just like where triple ko and similar cycles are mentioned).

It may be that top Chinese players do not like the positional superko rule, and so referees defer to them.

I think the text simply has a hard time explaining actual practice. These positions are rare but still frequent enough to have a decent number of precedents in pro games, maybe even dating back before written rules.

Right, I think what's going on is that like the Japanese players, the "official text" is not actually the rules that are used in reality. They write the text, and then ignore it, and one must look to what the actual practice is to try to guess the "real" rules.

[lightvector]

So, I'm at a little bit of a loss as to what to do. I guess I'll just make some decisions arbitrarily and accept any remaining mismatches as mismatches.

[Bill Spight]

It may be that top Chinese players do not like the positional superko rule, and so referees defer to them.

I think the text simply has a hard time explaining actual practice. These positions are rare but still frequent enough to have a decent number of precedents in pro games, maybe even dating back before written rules.

In the old days, before written rules, if a rules problem arose, you asked the best player you could to adjudicate. These days, the people who write the rules and the best players are rarely the same, although the rules writers are usually good players. Ing was an amateur. The J89 rules were not intended to match actual practice, and allowed a loophole for filling dame informally. That caused problems down the line. The AGA rules did not match actual practice, and actual practice differed, but the referees enforced the rules as written, for the most part. I doubt if the Chinese rules were intended to match actual practice, and it looks like they still don't. Not a problem if everyone agrees. The same thing happens with real life laws and regulations. Many are broken and the authorities wink or turn a blind eye.

[Bill Spight]

So, I'm at a little bit of a loss as to what to do. I guess I'll just make some decisions arbitrarily and accept any remaining mismatches as mismatches.

As far as the Chinese superko rule is concerned, look at it this way. You are the referee and your word is law.

Similarly with Japanese rules ambiguities. You are the judge, and you interpret the rules.

[Bill Spight]

Right, I think what's going on is that like the Japanese players, the "official text" is not actually the rules that are used in reality. They write the text, and then ignore it, and one must look to what the actual practice is to try to guess the "real" rules.

If the J89 rules were intended to match actual practice, they would have left the 1949 rules in place. But the 1949 rules were criticized for being illogical and ad hoc. (Ad hoc, to the thing itself, as in matching actual practice. ) They ended up with rules that were legalistic, ambiguous, difficult to understand and apply, while the top players continued doing as they always had. Damn the rules, full speed ahead.

IMHO, rules are made for the players, not the other way around. Before go had written rules, everybody knew how to play, now we have written rules, and nobody does.

[RobertJasiek]

I'm at a little bit of a loss as to what to do.

Why do you think that you must use official Japanese rules? Why not something simpler?
http://home.snafu.de/jasiek/sj.html