Life In 19x19

gennan wrote:How can players ever pass and at the same time deny that the game has ended?

Two passes only stop the game. Resumption is possible, but if requested J89 has the opponent start in it.

So with missed key move it is possible a player does not agree to end the game but (either player) cannot afford to request resumption either, hence the both lose hack (there may also be a logical problem here).

About translation, IIRC the current one is not bad as a translation (Davies), but was probably aimed at players not theorists. So instead of expecting rigid definitions of all details you need to use both common go sense and common English sense (similarly to the original Japanese likely).

A group that can be saved by a starting defensive move is not alive, the first move is what would make it alive - thus it wasn't alive (but unsettled) originally. And text says not alive => dead, NOT not dead => alive.

jann wrote:And text says not alive => dead, NOT not dead => alive.

Oops I am a little lost Jann.
For a mathematical point of view
if "not A => B" then don't we have "not B => A" ?

The Nihon Kiin 1989 Rules contain a defition of "alive".
Everything that does not match this defition is "dead".

As a matter of course, everything that is "not dead", is "alive".

I assume that it might be possible to write a ruleset that contains a defition of "dead".
Then everything that does not match this defition is "alive".

And again, everything that is "not alive", is "dead".

Usually, the more positive first option is chosen by the authors.

Gérard TAILLE wrote:if "not A => B" then don't we have "not B => A" ?

Unsettled groups (C) could be treated alive (A) or dead (B) depending on the definition.

jann wrote:About translation, IIRC the current one is not bad as a translation (Davies), but was probably aimed at players not theorists. So instead of expecting rigid definitions of all details you need to use both common go sense and common English sense (similarly to the original Japanese likely).

That is a good point Jann. We have to try to use common go sense to resolve difficult positions. Let's try. Assume a game stops in a position where playing a confirmation phase may be very difficult (look as the stupid example (sorry Cassandra) showed in viewtopic.php?p=265943#p265943. That means that by playing this confirmation phase both players may very easily makes mistakes.

To simplify the discussion let's simulate such difficulties on a trivial example with trivial mistakes.

Click Here To Show Diagram Code

[go]$$W Confirmation phase
$$ -------------
$$ | . . . X O |
$$ | X X X X O |
$$ | O O O O O |
$$ | . . . . . |
$$ | . . . . . |
$$ -------------[/go]

We are in the confirmation phases (both players have passed and nobobody request a resumption of the game).

white : black stones are dead
black : I am not convinced so, please start a confirmation phase and prove I am not alive
white : OK

and it follows the sequence (with two mistakes)

Click Here To Show Diagram Code

[go]$$W Confirmation phase
$$ -------------
$$ | 1 3 2 X O |
$$ | X X X X O |
$$ | O O O O O |
$$ | . . . . . |
$$ | . . . . . |
$$ -------------[/go]

black: OK I am not alive with this sequence but may be I made a mistake. Because it is up to you to prove black is not alive I consider I can have another chance to try to live

here the second sequence

Click Here To Show Diagram Code

[go]$$W Confirmation phase
$$ -------------
$$ | 1 2 . X O |
$$ | X X X X O |
$$ | O O O O O |
$$ | . . . . . |
$$ | . . . . . |
$$ -------------[/go]

white : well you are alive but maybe I made also a mistake
black : yes OC, but you claimed black stones were dead and I ask you to prove and explain that point. If you fail that means that you are not really in a position to prove black stones are not alive => black stones are alive.

IOW : who is in charge of the proof? The attacker or the defender?
Maybe we can say both but in that case that could lead to endless discussions.
My preference is to say that the attacker is in charge of the proof. In that case, during the analysis, the attacker is not allowed to change one of her move while the defender is allowed to try several moves.

One idea to solve the problem.
The attacker starts the confirmation phase
Each player must play in say 30"
At each time the defender may change one of her move and resume the game but the number of changes is limited to say 3.
That way any player (even beginners) may give a result for their game within an acceptable time.

Some people think Japanese analysis is about theoretical perfect play. I doubt it is necessarily so, having the players play to their abilities could also work. But trying a (reasonably) few possible attacking and defending moves should fit in for both sides. Exact (time/attempt) limits are not defined - just like with (non-infinite) resumptions.

I support jann's opinion.

Go is a game of mutual agreement. If both sides are fine with their result, nothing can be wrong with it.
Remember that tango is only for TWO.

In tournaments, go is not a game of mutual agreement in the sense of collusion on an arbitrary result. E.g., fabrication of a jigo to share prize moneys resulted in penalty on two Russian 6d in a London Grand Prix. E.g., intentionally negotiating the winner between two Russians to let a third Russian win a French tournament on SOS resulted in penalty. J89 mutual agreement means agreeing on what perfect play analysis is also in the interest of fair tournament competition.

Dear Robert,

as I already mentioned earlier, there is NO "tournament" referenced in the Nihon Kiin 1989 Rules. You are overstretching things a bit.

"Mutual agreement" means an agreement between the two players, not with God.

J89 were written for pros and tournament games and contain a few tournament-like rules. I know what mutual agreement means in English but this is not the J89-intended meaning.

RobertJasiek wrote:J89 were written for pros and tournament games and contain a few tournament-like rules. I know what mutual agreement means in English but this is not the J89-intended meaning.

No doubt J89 is a part of tournament rule, but tournament rules must add specific rules on which each player must agree. One trivial example is time constraint OC. In that sense, when I propose to add a rule like 30" per move in the confirmation phase Cassandra is right to say that does not address the J89 rule but rather tournament rules that can be seen as agreements between players for that tournament.

Let's come back on the confrimation phase and on the issue of adding moves before stopping the game.

Click Here To Show Diagram Code

[go]$$W White to play
$$ -----------------
$$ | O X . X O . O |
$$ | . O X X X O O |
$$ | O O O X O O O |
$$ | . O . O O X X |
$$ | O O O X X X . |
$$ | X X X X . X X |
$$ | . . . . . X . |
$$ -----------------[/go]

My question is the following (I am not quite sure of the answer):
To assure black stones at the top are dead, should white add a move before passing and stopping the game?

RobertJasiek wrote:I know what mutual agreement means in English but this is not the J89-intended meaning.

I doubt that you have any idea of what "mind connection" means in Japan.

Gérard TAILLE wrote:To assure black stones at the top are dead, should white add a move before passing and stopping the game?

The question is NOT the status of Black's stones, these are dead for sure, as Black cannot prevent their capture.

I think in J89 the last position needs an extra W move, to prevent B abuse of the pass-for-ko rule (B dead but some W stones too).

Note though that rule is known to be flawed, there were some old counterexamples for it, and recently lightvector found even more convincing ones. This example is similar.