kvasir wrote:
This comment was about pass-ko in j89 status confirmation. Both black and white are dead in j89 status confirmation in the first position (I gave the line for capturing white already), it would seem that white is dead in exactly the same way in the second one. Brushing aside the need for a reinforcement move in the first positions doesn't seem to me to be valid in j89 status confirmation. I was curious if your no-ban rule would change how black can capture white during status confirmation, or if this issue was outside of scope.
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | . . X X X X O X . .
$$ | X X O X O X O X . .
$$ | X O . O . O O X . .
$$ | O . O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]
Maybe I am wrong but when in a position like the one above, black is dead in all area scoring rules, and is dead in NORMAL play in any japanese rule, even if it black to move, then I consider the intention of japanese rule should be that white does not need a reinforcement move.
In J89 it is not the case => it is an unexpected side effect of pass-for-ko rule (as is the closed cycle in the double ko).
How it works with "no ban in double ko" rule:
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | . . X X X X O X . .
$$ | X X O X O X O X . .
$$ | X O 1 O 3 O O X . .
$$ | O 2 O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | . . X X X X O X . .
$$ | X X M X M X O X . .
$$ | X O X O X O O X . .
$$ | O O O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]
the two ko are "strong double ko" and the position is critical (black has taken the two ko) => white can ignore the pass-for-ko request.
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | . . X X X X O X . .
$$ | X X 4 X M X O X . .
$$ | X O X O X O O X . .
$$ | O O O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]
the move

is allowed by the "no ban in double ko" rule (white cannot take the other ko due to the regular ko ban).
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | . . X X X X O X . .
$$ | X X O X M X O X . .
$$ | X O M O X O O X . .
$$ | O O O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]
After white

the pass-for-ko request remain active because the position is no more critical => white while be able to connect her ko making two eyes and black group will be dead => white, in the initial position, do not need to add a move.
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | X . . . . X X X
$$ | . X X X X X O X . .
$$ | X X W X W X O X . .
$$ | X O . O . O O X . .
$$ | O . O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]
This position is quite different because black is already alive. The "no ban in double ko" rule avoid to declare all white stones dead.
The result is exactly the same as the following position
- Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | X . . . . X X X
$$ | . X X X X X O X . .
$$ | X X . X O X O X . .
$$ | X O X O . O O X . .
$$ | O O O O O O X X . .
$$ | O . O . O X X . . .
$$ | O O O O X . . . .
$$ | X X X X X . . . . .[/go]
I suspect that J89 conclude to a large seki due to the unresolved ko => that is the result with "no ban in double ko" rule.