GT territory rules:: Honte's loops and cycles

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 3:28 am

Loops with a cycle-length of pseudo 6 (contd)

The earth suddenly trembled between rubble and scrub - an earthquake!
There was a huge landslide ahead of us that blocked access to District 6 for all eternity. It is estimated that "He Who Cannot Be Named" had his hands in it magically.

We later heard that GT City's central office building was also collapsed by the earthquake. Thank goodness no one was killed or injured because everyone there was on a research expedition.
There are rumors that GT City will not rebuild its central building, but will leave its ruins as a reminder of a glorious past in which people still believed in the healing properties of "loops". After all, they have more than enough empty office space.

Now let's share what was seen after the earthquake.

##### After the earthquake #####

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | . X . X . X | $$ | X O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

===== GT territory rules =====

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | 1 X 2 X . X | $$ | X O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | . 3 . X . X | $$ | . O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | . Y . Y . X | $$ | . O Y X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

created a ko-shape.

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | 4 X . X . X | $$ | . O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | Q X . X . X | $$ | . Q X X X X | $$ | Q O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

created a ko-shape.

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | Q X . X . X | $$ | 5 Q X X X X | $$ | Q O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

captures into a ko-shape.

Click Here To Show Diagram Code: [go]$$B :w6: pass $$ +-------------+ $$ | Q X . X . X | $$ | ? Q X X X X | $$ | Q O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

passes.
The resulting position is a "critical" one.

White claims for creating a "permanently prohibited ko", making a ko-capture at the shadowed point taboo for Black.

Click Here To Show Diagram Code: [go]$$Bm7 $$ +-------------+ $$ | 1 X 2 X . X | $$ | X O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm7 $$ +-------------+ $$ | . 3 . X . X | $$ | . O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm7 $$ +-------------+ $$ | . Y . Y . X | $$ | . O Y X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

created a ko-shape.

Click Here To Show Diagram Code: [go]$$Bm7 $$ +-------------+ $$ | 4 X . X . X | $$ | . O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm7 $$ +-------------+ $$ | Q X . X . X | $$ | ? Q X X X X | $$ | Q O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

created a "permanently prohibited ko".

Click Here To Show Diagram Code: [go]$$Bm7 :b11: pass $$ +-------------+ $$ | Q X . X . X | $$ | ? Q X X X X | $$ | Q O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Black can only "pass", as the shadowed point has become taboo for him.

Click Here To Show Diagram Code: [go]$$Bm11 :b13: pass $$ +-------------+ $$ | O X 2 X 4 X | $$ | . O X X X X | $$ | O O O X O O | $$ | . . X O O . | $$ | X X X X O O | $$ | . X . X O . | $$ +-------------+[/go]

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | W . W . W . | $$ | . W . . . . | $$ | W W W . W W | $$ | . . X W W . | $$ | X X X X W W | $$ | . X . X W . | $$ +-------------+[/go]

Two eye formation for White, but NOT occupying the entire board.

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | @ # . # . # | $$ | . @ # # # # | $$ | @ @ @ # @ @ | $$ | T T X @ @ . | $$ | X X X X @ @ | $$ | . X . X @ . | $$ +-------------+[/go]

NO territory for White on the entire board.

White should have taken Black's stones at the top off the board before the game stopped, and occupied the DAME of

thereafter.

===== "Two-eyed alive" world =====

As can be seen above, the cycle as a length of 6, but it includes a White "pass", so the cycle length is "pseudo 6" only.

-------------------------

The cycle-length pseudo 6 fulfills the condition

cl = 2 + 4n (n = 0, 1, 2, 3, ...).

Therefore, the last GENUINE move of that (uninterrupted) cycle is forbidden.

Next run:

As can be seen above, White will be able to create a two-eye-formation in the upper part of the board by capturing Black's stones at the top.

-------------------------

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | a Z b Z c Z | $$ | Z W Z Z Z Z | $$ | W W W Z W W | $$ | T T B W W . | $$ | B B B B W W | $$ | . B . B W . | $$ +-------------+[/go]

Concluding result of status confirmation.

Black should have occupied the DAME

before the game stopped, forcing White to take his stones at the top off the board with moves at a, b, and c.

Gérard TAILLE · Post by **Gérard TAILLE** » Sun Aug 29, 2021 6:39 am

Cassandra wrote:
$$B
$$ +-------------+
$$ | . X . X . X |
$$ | X O X X X X |
$$ | O O O X O O |
$$ | d d B O O . |
$$ | B B B B O O |
$$ | e B e B O . |
$$ +-------------+
Click Here To Show Diagram Code
[go]$$B $$ +-------------+ $$ | . X . X . X | $$ | X O X X X X | $$ | O O O X O O | $$ | d d B O O . | $$ | B B B B O O | $$ | e B e B O . | $$ +-------------+[/go]

Oops it seems the earthquake has not only attacked the structure of the building of the city but also the foundation of the rule itself.
In either rule, if you look at the marked black group you see two eyes at "e" locations and two dame points at "d" locations. => obviouly the game is not finished because you cannot imagine black allowing the existence of these dame with the consequence that the eye points "e" will not be counted as territory.

OK let's assume that black decides to pass

Can white claim for a territory at the top of the board?

Click Here To Show Diagram Code: [go]$$B $$ +-------------+ $$ | . X . X . X | $$ | X O X X X X | $$ | O O O X O O | $$ | C C B O O . | $$ | X X X B O O | $$ | . X . B O . | $$ +-------------+[/go]

Always due to the dame "d" it is not possible because the outside border marked here above is not valid (two empy locations)

With this kind of unfinished game you not even need to start an hupothetical play.

Surely I have to find a safe-deposit-box in order to protect my rule against an earthquake.

Gérard TAILLE · Post by **Gérard TAILLE** » Sun Aug 29, 2021 7:14 am

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | O X X X . X X | $$ | a O X X X X b | $$ | O . O O X O X | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+ $$[/go]

How do you recognise a double ko? Depending of the environment you cannot replace the position above by the following can you?

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------+ $$ | . X X X . X X | $$ | O O X X X X X | $$ | O . O O X O . | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+ $$ {AR A7 A6} $$ {AR G5 G6} $$[/go]

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 7:25 am

Gérard TAILLE wrote:
$$B
$$ +---------------+
$$ | O X X X . X X |
$$ | a O X X X X b |
$$ | O . O O X O X |
$$ | O O O . O O O |
$$ | . . . O . O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+
$$
Click Here To Show Diagram Code
[go]$$B $$ +---------------+ $$ | O X X X . X X | $$ | a O X X X X b | $$ | O . O O X O X | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+ $$[/go]
How do you recognise a double ko? Depending of the environment you cannot replace the position above by the following can you?
$$Bc
$$ +---------------+
$$ | . X X X . X X |
$$ | O O X X X X X |
$$ | O . O O X O . |
$$ | O O O . O O O |
$$ | . . . O . O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+
$$ {AR A7 A6}
$$ {AR G5 G6}
$$
Click Here To Show Diagram Code
[go]$$Bc $$ +---------------+ $$ | . X X X . X X | $$ | O O X X X X X | $$ | O . O O X O . | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+ $$ {AR A7 A6} $$ {AR G5 G6} $$[/go]

I suppose that...

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------+ $$ | T X X X C X X | $$ | Q O X X X X Y | $$ | O C O O X O T | $$ | O O O C O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+[/go]

... (two eyes vs. one eye) will make you easier understand that Black's group at the top is dead than...

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | O X X X . X X | $$ | 1 O X X X X . | $$ | O 2 O O X O X | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+$$[/go]

... playing

in your head.

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | M X X X C X X | $$ | X P X X X X M | $$ | O O O O X P X | $$ | O O O C O O O | $$ | . . . O C O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+$$[/go]

Black's group has one genuine, and two false, eyes -- and so is dead. Same result as after Honte's magic spell.

Gérard TAILLE · Post by **Gérard TAILLE** » Sun Aug 29, 2021 8:21 am

Cassandra wrote:
Gérard TAILLE wrote:
$$B
$$ +---------------+
$$ | O X X X . X X |
$$ | a O X X X X b |
$$ | O . O O X O X |
$$ | O O O . O O O |
$$ | . . . O . O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+
$$
Click Here To Show Diagram Code
[go]$$B $$ +---------------+ $$ | O X X X . X X | $$ | a O X X X X b | $$ | O . O O X O X | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+ $$[/go]
How do you recognise a double ko? Depending of the environment you cannot replace the position above by the following can you?
$$Bc
$$ +---------------+
$$ | . X X X . X X |
$$ | O O X X X X X |
$$ | O . O O X O . |
$$ | O O O . O O O |
$$ | . . . O . O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+
$$ {AR A7 A6}
$$ {AR G5 G6}
$$
Click Here To Show Diagram Code
[go]$$Bc $$ +---------------+ $$ | . X X X . X X | $$ | O O X X X X X | $$ | O . O O X O . | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+ $$ {AR A7 A6} $$ {AR G5 G6} $$[/go]
I suppose that...

$$Bc
$$ +---------------+
$$ | T X X X C X X |
$$ | Q O X X X X Y |
$$ | O C O O X O T |
$$ | O O O C O O O |
$$ | . . . O . O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+
Click Here To Show Diagram Code
[go]$$Bc $$ +---------------+ $$ | T X X X C X X | $$ | Q O X X X X Y | $$ | O C O O X O T | $$ | O O O C O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+[/go]
... (two eyes vs. one eye) will make you easier understand that Black's group at the top is dead than...

$$B
$$ +---------------+
$$ | O X X X . X X |
$$ | 1 O X X X X . |
$$ | O 2 O O X O X |
$$ | O O O . O O O |
$$ | . . . O . O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+$$
Click Here To Show Diagram Code
[go]$$B $$ +---------------+ $$ | O X X X . X X | $$ | 1 O X X X X . | $$ | O 2 O O X O X | $$ | O O O . O O O | $$ | . . . O . O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+$$[/go]
... playing in your head.

$$B
$$ +---------------+
$$ | M X X X C X X |
$$ | X P X X X X M |
$$ | O O O O X P X |
$$ | O O O C O O O |
$$ | . . . O C O . |
$$ | . . . O O O O |
$$ | . . . . . . . |
$$ +---------------+$$
Click Here To Show Diagram Code
[go]$$B $$ +---------------+ $$ | M X X X C X X | $$ | X P X X X X M | $$ | O O O O X P X | $$ | O O O C O O O | $$ | . . . O C O . | $$ | . . . O O O O | $$ | . . . . . . . | $$ +---------------+$$[/go]
Black's group has one genuine, and two false, eyes -- and so is dead. Same result as after Honte's magic spell.

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | O X X X . X X | $$ | a O X X X X b | $$ | O . O O X O X | $$ | O O O . O O O | $$ | X X X O . O . | $$ | X . X O O O O | $$ | . X X X X X X | $$ +---------------+ $$[/go]

Honte's magic wand will clearly disadvantaged black won't it? => it is almost a double ko but it is not really one.

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 10:32 am

About compositions of four ko-shapes

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O X X X O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

This is the example with four ko-shapes that Gérard kindly provided to me.

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X Y O O O | $$ | O O Y b X c Y O O | $$ | O O Q Y X Y Q O O | $$ | e O a Q X Q d O f | $$ +-------------------+[/go]

The four ko-shapes are a, b, c and d.

All three groups in question have TWO liberties each.
-- White's group at the left has one liberty at e in her eye, and another one in the neighbored double-ko (at a or b).
-- Black's group in the centre has one liberty in the double-ko at left (at a or b), and another one in the double-ko at right (at c or d)
-- White's group at the left has one liberty at f in her eye, and another one in the neighbored double-ko (at c or d).

Thus, we can expect this position being a seki.

##### Honte's magic DOUBLE-KO spell #####

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O T Y X Y T O O | $$ | O O O X X X O O O | $$ | . O Q T X T Q O . | $$ +-------------------+[/go]

After Honte used his magic wand...

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . B B B B . . | $$ | . B B B @ @ B B . | $$ | B B @ @ # @ @ B B | $$ | @ @ @ # # # @ @ @ | $$ | @ @ . # # # . @ @ | $$ | @ @ @ # # # @ @ @ | $$ | . @ @ . # . @ @ . | $$ +-------------------+[/go]

... we can easily see that the position is seki.

No wonder that this is the fastest method, as magic was involved.

##### GT territory rules #####

Second fastest is using the GENUINE quadruple-ko cycle.

Click Here To Show Diagram Code: [go]$$B GENUINE quadruple-ko cycle $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X 2 X 4 X O O | $$ | O O O X X X O O O | $$ | . O 1 O X O 3 O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B GENUINE quadruple-ko cycle $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O 5 O X O 7 O O | $$ | O O O X X X O O O | $$ | . O X 6 X 8 X O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B GENUINE quadruple-ko cycle $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O X X X O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

Same position as eight moves before.

Neither side will ever create a two-eye-formation in the lower part of the board.
==> NO territory.

--------------------------

Using the "permanent prohibited ko" feature will neither shorten nor ease the sequences required.
It seems to me that "permanent prohibited ko" will be most useful in ASYMMETRICAL positions.

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O Q X X X O O O | $$ | . O 1 Q X O . O . | $$ +-------------------+[/go]

We will start with trying to find out, whether White will be able to create a two-eye-formation at the bottom.

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X O O O | $$ | O O Y 2 X . X O O | $$ | O O O Y X X O O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups; :b3: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X O O O | $$ | O O T P X . X O O | $$ | O O O Y X X O O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

Black also claims "permanently prohibited ko" for

.

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X Y O O O | $$ | O O . O X 4 Y O O | $$ | O O O X X Y O O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O Q X X X O O O | $$ | O O 5 Q X O . O O | $$ | O O Q X X X O O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X O . O O | $$ | O O O Y X X O O O | $$ | . O Y 6 X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X Q O O | $$ | O O Y M X Q 7 O O | $$ | O O O Y X X Q O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

White must not capture into the ko-shape at left.

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups; :w8: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X Q O O | $$ | O O Y M X T Z O O | $$ | O O O Y X X Q O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

White must not capture into the ko-shape at left, instead.
White also claims "permanently prohibited ko" for

.

Click Here To Show Diagram Code: [go]$$B Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O Q X X X O O O | $$ | . O 9 Q X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$Wm10 Status confirmation for White groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X Y O O O | $$ | O O Y M X 1 Y O O | $$ | O O O Y X Y O O O | $$ | 2 O X . X O . O . | $$ +-------------------+[/go]

must not capture into the ko-shape at left, instead.

==> NO White territory.

------------------------

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X Y O O O | $$ | O O X . X 1 Y O O | $$ | O O O X X Y O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

Will Black be able to create a two-eye-formation at the bottom?

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X O . O O | $$ | O O O X X X Q O O | $$ | . O . O X Q 2 O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups; :w3: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X O . O O | $$ | O O O X X X Q O O | $$ | . O . O X T Z O . | $$ +-------------------+[/go]

White also claims "permanently prohibited ko" for

.

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X Q O O | $$ | O O X . X Q 4 O O | $$ | O O O X X X Q O O | $$ | . O . O X . X O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O X X Y O O O | $$ | . O . O X 5 Y O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups; :b6: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O X X Y O O O | $$ | . O . O X P T O . | $$ +-------------------+[/go]

Black also claims "permanently prohibited ko" for

.
This does not have any effect, as Black must not re-capture into that ko-shape anyway.

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X Y O O O | $$ | O O X . X 7 Y O O | $$ | O O O X X Y O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X O . O O | $$ | O O Q X X X Q O O | $$ | . O 8 Q X Q M O . | $$ +-------------------+[/go]

Black must not re-capture at right, instead.

Click Here To Show Diagram Code: [go]$$W Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X O O O | $$ | O O Y 9 X O . O O | $$ | O O O Y X X O O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X Q O O | $$ | O O . O X Q 1 O O | $$ | O O O X X X Q O O | $$ | . O X . X Q M O . | $$ +-------------------+[/go]

Black must not re-capture into the lower ko-shape.

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups; :w11: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X Q O O | $$ | O O . O X T Z O O | $$ | O O O X X X Q O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

White also claims "permanently prohibited ko" for

.

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O Q X X X O O O | $$ | O O 3 Q X . X O O | $$ | O O Q X X X O O O | $$ | . O X . X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O Y X X O O O | $$ | . O Y 4 X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups; :b14: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O Y X X Q O O | $$ | . O T P X Q M O . | $$ +-------------------+[/go]

Black must not re-capture into the lower ko-shape at right, instead.
Black also claims "permanently prohibited ko" for

.

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X O O O | $$ | O O Y 6 X . X O O | $$ | O O O Y X X O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bm10 Status confirmation for Black groups; :b16: pass $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X X O O O | $$ | O O . O X 8 X O O | $$ | O O O Y X X Q O O | $$ | . O . O X Q M O . | $$ +-------------------+[/go]

Black must not re-capture into the lower ko-shape at right.

==> NO Black territory.

Gérard TAILLE · Post by **Gérard TAILLE** » Sun Aug 29, 2021 11:04 am

Cassandra wrote:About compositions of four ko-shapes

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . X X X X . . |
$$ | . X X X O O X X . |
$$ | X X O O X O O X X |
$$ | O O O X X X O O O |
$$ | O O X . X . X O O |
$$ | O O O X X X O O O |
$$ | . O . O X O . O . |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O X X X O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]
This is the example with four ko-shapes that Gérard kindly provided to me.

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . X X X X . . |
$$ | . X X X O O X X . |
$$ | X X O O X O O X X |
$$ | O O O Y X Y O O O |
$$ | O O Y b X c Y O O |
$$ | O O Q Y X Y Q O O |
$$ | e O a Q X Q d O f |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X Y O O O | $$ | O O Y b X c Y O O | $$ | O O Q Y X Y Q O O | $$ | e O a Q X Q d O f | $$ +-------------------+[/go]
The four ko-shapes are a, b, c and d.

All three groups in question have TWO liberties each.
-- White's group at the left has one liberty at e in her eye, and another one in the neighbored double-ko (at a or b).
-- Black's group in the centre has one liberty in the double-ko at left (at a or b), and another one in the double-ko at right (at c or d)
-- White's group at the left has one liberty at f in her eye, and another one in the neighbored double-ko (at c or d).

Thus, we can expect this position being a seki.

##### Honte's magic DOUBLE-KO spell #####

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . X X X X . . |
$$ | . X X X O O X X . |
$$ | X X O O X O O X X |
$$ | O O O X X X O O O |
$$ | O O T Y X Y T O O |
$$ | O O O X X X O O O |
$$ | . O Q T X T Q O . |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O T Y X Y T O O | $$ | O O O X X X O O O | $$ | . O Q T X T Q O . | $$ +-------------------+[/go]
After Honte used his magic wand...

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . B B B B . . |
$$ | . B B B @ @ B B . |
$$ | B B @ @ # @ @ B B |
$$ | @ @ @ # # # @ @ @ |
$$ | @ @ . # # # . @ @ |
$$ | @ @ @ # # # @ @ @ |
$$ | . @ @ . # . @ @ . |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . B B B B . . | $$ | . B B B @ @ B B . | $$ | B B @ @ # @ @ B B | $$ | @ @ @ # # # @ @ @ | $$ | @ @ . # # # . @ @ | $$ | @ @ @ # # # @ @ @ | $$ | . @ @ . # . @ @ . | $$ +-------------------+[/go]
... we can easily see that the position is seki.

No wonder that this is the fastest method, as magic was involved.

##### GT territory rules #####

Second fastest is using the GENUINE quadruple-ko cycle.

$$B GENUINE quadruple-ko cycle
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . X X X X . . |
$$ | . X X X O O X X . |
$$ | X X O O X O O X X |
$$ | O O O X X X O O O |
$$ | O O X 2 X 4 X O O |
$$ | O O O X X X O O O |
$$ | . O 1 O X O 3 O . |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B GENUINE quadruple-ko cycle $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X 2 X 4 X O O | $$ | O O O X X X O O O | $$ | . O 1 O X O 3 O . | $$ +-------------------+[/go]

$$B GENUINE quadruple-ko cycle
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . X X X X . . |
$$ | . X X X O O X X . |
$$ | X X O O X O O X X |
$$ | O O O X X X O O O |
$$ | O O 5 O X O 7 O O |
$$ | O O O X X X O O O |
$$ | . O X 6 X 8 X O . |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B GENUINE quadruple-ko cycle $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O 5 O X O 7 O O | $$ | O O O X X X O O O | $$ | . O X 6 X 8 X O . | $$ +-------------------+[/go]

$$B GENUINE quadruple-ko cycle
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . X X X X . . |
$$ | . X X X O O X X . |
$$ | X X O O X O O X X |
$$ | O O O X X X O O O |
$$ | O O X . X . X O O |
$$ | O O O X X X O O O |
$$ | . O . O X O . O . |
$$ +-------------------+
Click Here To Show Diagram Code
[go]$$B GENUINE quadruple-ko cycle $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O X . X . X O O | $$ | O O O X X X O O O | $$ | . O . O X O . O . | $$ +-------------------+[/go]
Same position as eight moves before.

"GT territory rule" do not handle loops by trying to recognize them really (I mean recognizing that the same position appeared already in the previous moves). "GT territory rule" looks only to an infinity of "critical" positions. Assuming white claim for a territory at the bottom of the board then it is black to play and obviously black can play only atari moves to which white has to answer by puting a stone on the board => no "critical" positions at all => no "permanent prohibited ko" => the loop cannot be break => No territory.
That's all you can do with "GT territory rule". Remember, if the attacker wants to break a loop she must first prove she can reach "critical" positions an infinite number of time, with the defender playing first in the hypothetical play. Here the attacker cannot even reach only one "critical" position => the loop cannot be breaked.

In J2003 the analyse seems more complicated if not strange: the big white and black groups of stones are all alive, the four isolated stones involved in the ko are dead (they can be captured and no new permanently alive stone can be created) => the four empty locations in the ko are dame (they are not surrounded by only living stones) => the three big alive groups have dame => seki

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 11:56 am

Gérard TAILLE wrote:"GT territory rule" do not handle loops by trying to recognize them really (I mean recognizing that the same position appeared already in the previous moves). "GT territory rule" looks only to an infinity of "critical" positions. Assuming white claim for a territory at the bottom of the board then it is black to play and obviously black can play only atari moves to which white has to answer by puting a stone on the board => no "critical" positions at all => no "permanent prohibited ko" => the loop cannot be break => No territory.
That's all you can do with "GT territory rule". Remember, if the attacker wants to break a loop she must first prove she can reach "critical" positions an infinite number of time, with the defender playing first in the hypothetical play. Here the attacker cannot even reach only one "critical" position => the loop cannot be breaked.

It seems I wrote a throwback to GT City's Roaring Twenties.

You too still seem to like to remember that "looping" time.

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 12:48 pm

"HIGHLANDER 2 –– At the very most there can be one"

Honte's magic DOUBLE-ko spell reduces the number of ko-shapes that are really effective in a formation under status consideration.
The number of ko-shapes effectively remaining will be

1 or 0.

ONE ko-shape:

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | . Q . Q . X . | $$ | O O Q X X X . | $$ | X X X X . . . | $$ | . . . . . . . | $$ | . . . . . . . |[/go]

Effective number of ko-shapes: 1

TWO ko-shapes:

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | . Y . Y O X . | $$ | X X Y O O X . | $$ | Q X O . O X . | $$ | . Q O O O X . | $$ | Q O X X X X . | $$ | X X X . . . . | $$ | . . . . . . . | $$ +---------------+[/go]

Two ko-shapes.

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | . X Y T O X . | $$ | X X X O O X . | $$ | T X O . O X . | $$ | Q O O O O X . | $$ | O O X X X X . | $$ | X X X . . . . | $$ | . . . . . . . | $$ +---------------+[/go]

After Honte used his magic wand...

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | . X X . O X . | $$ | X X X O O X . | $$ | . X O . O X . | $$ | O O O O O X . | $$ | O O X X X X . | $$ | X X X . . . . | $$ | . . . . . . . | $$ +---------------+[/go]

Effective number of ko-shapes: 0

THREE ko-shapes:

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------+ $$ | . Q O . O . O X . Y O . O | $$ | Q X X O O O O X Y Q O O O | $$ | X X . X X X O X Q . O X X | $$ | . . X , X O X X X Q O X X | $$ | X X X X X O X . X O X X . | $$ | O O O O X O X X X O X . X | $$ | . . . O O O O O O X X X X | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . |[/go]

Three ko-shapes.

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------+ $$ | . Q O . O . O X Y T O . O | $$ | Q X X O O O O X X O O O O | $$ | X X . X X X O X T Q O X X | $$ | . . X , X O X X X O O X X | $$ | X X X X X O X . X O X X . | $$ | O O O O X O X X X O X . X | $$ | . . . O O O O O O X X X X | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . |[/go]

After Honte used his magic wand...

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------+ $$ | . Q O . O . O X X . O . O | $$ | Q X X O O O O X X O O O O | $$ | X X . X X X O X . O O X X | $$ | . . X , X O X X X O O X X | $$ | X X X X X O X . X O X X . | $$ | O O O O X O X X X O X . X | $$ | . . . O O O O O O X X X X | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . |[/go]

Effective number of ko-shapes: 1

FOUR ko-shapes:

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O Y X Y O O O | $$ | O O Y . X . Y O O | $$ | O O Q Y X Y Q O O | $$ | . O . Q X Q . O . | $$ +-------------------+[/go]

Four ko-shapes.

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O T Y X Y T O O | $$ | O O O X X X O O O | $$ | . O Q T X T Q O . | $$ +-------------------+[/go]

After Honte used his magic wand...

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . . X X X X . . | $$ | . X X X O O X X . | $$ | X X O O X O O X X | $$ | O O O X X X O O O | $$ | O O . X X X . O O | $$ | O O O X X X O O O | $$ | . O O . X . O O . | $$ +-------------------+[/go]

Effective number of ko-shapes: 0

Gérard TAILLE · Post by **Gérard TAILLE** » Sun Aug 29, 2021 1:32 pm

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | O . O X a X O O b | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+ $$[/go]

Two kos.
Applying Honte's magic wand would be a disaster for white wouldn't it?

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 2:32 pm

Gérard TAILLE wrote:
$$B
$$ +-------------------+
$$ | O . O X a X O O b |
$$ | O O O O X X O X O |
$$ | . X X X . X O X X |
$$ | X X X X X X O . . |
$$ | O O O O O X O O O |
$$ | . . . O O X X X X |
$$ | . . . . O O O O O |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ +-------------------+
$$
Click Here To Show Diagram Code
[go]$$B $$ +-------------------+ $$ | O . O X a X O O b | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+ $$[/go]
Two kos.
Applying Honte's magic wand would be a disaster for white wouldn't it?

Thank you for giving me the opportunity to clarify what a "DOUBLE-Ko" is.

Sensei's Library wrote:Double ko refers to any situation in which a group has two kos, and these determine its status.

Click Here To Show Diagram Code: [go]$$B Ko at left $$ +-------------------+ $$ | O . Q Y T Y O O . | $$ | O O O Q Y X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Groups connected to the ko at left $$ +-------------------+ $$ | Q . Q Y T Y O O . | $$ | Q Q Q Q Y Y O X O | $$ | . Y Y Y . Y O X X | $$ | Y Y Y Y Y Y O . . | $$ | O O O O O Y O O O | $$ | . . . O O Y Y Y Y | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

------------------------

Click Here To Show Diagram Code: [go]$$B Ko at right $$ +-------------------+ $$ | O . O X . X O Q T | $$ | O O O O X X O Y Q | $$ | . X X X . X O X Y | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Groups connected to the ko at right $$ +-------------------+ $$ | O . O X . X Q Q T | $$ | O O O O X X Q Y Q | $$ | . X X X . X Q Y Y | $$ | X X X X X X Q . . | $$ | O O O O O X Q Q Q | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

------------------------

NONE of the groups is connected to BOTH ko-shapes, so Honte's magic DOUBLE-ko spell will have no effect here.

++++++++++++++++++++++++

The topic above is strongly connected with what a FALSE EYE is.

Sensei's Library wrote:A false eye is something which looks like an eye, but shouldn't be counted as part of the group's eye space because some of the surrounding stones can be put into atari.

Honte's spell only works on false eyes.

Click Here To Show Diagram Code: [go]$$B Ko at left => false eye $$ +-------------------+ $$ | O . O X M X O O . | $$ | O O O P X X O X O | $$ | 1 X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

is an atari.
If White captured into that ko, it would be her stone that was in atari.

Click Here To Show Diagram Code: [go]$$B Ko at left => false eye $$ +-------------------+ $$ | O . O X 1 X O O . | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

False eyes in a seki can be filled by EITHER side (or NEITHER side, as with a GENUINE double-ko, to be complete).
Black here.

Click Here To Show Diagram Code: [go]$$W Ko at left => false eye $$ +-------------------+ $$ | O . O X 1 X O O . | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$W Ko at left => false eye; :b2: pass $$ +-------------------+ $$ | O . O 3 O X O O . | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

White here.

------------------------

Click Here To Show Diagram Code: [go]$$B Ko at right => NO false eye $$ +-------------------+ $$ | O . O X . X O O C | $$ | O O O O X X O B O | $$ | . X X X . X O X X | $$ | X X X X X X O 1 . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

is a self-atari!

Click Here To Show Diagram Code: [go]$$B Ko at right => NO false eye $$ +-------------------+ $$ | O . O X . X O O 1 | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B Ko at right => NO false eye; :w2: pass $$ +-------------------+ $$ | O . O X . X O O X | $$ | O O O O X X O X 3 | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

Black is able to fill the ko-shape.

Click Here To Show Diagram Code: [go]$$W Ko at right => NO false eye $$ +-------------------+ $$ | O . O X . X O O 1 | $$ | O O O O X X O X O | $$ | . X X X . X O X X | $$ | X X X X X X O . . | $$ | O O O O O X O O O | $$ | . . . O O X X X X | $$ | . . . . O O O O O | $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ +-------------------+[/go]

White is NOT!

==> That ko-shape is a genuine part of White's eye space!

Cassandra · Post by **Cassandra** » Sun Aug 29, 2021 2:42 pm

Honte's magic SINGLE-ko spell –– Usually there is NO ko at the beginning of status confirmation!

##### False eyes in status confirmation #####

Probably you already noticed that EVERY ko-shape that effectively remained after the application of Honte's magic DOUBLE-ko spell in my respective posting above is nothing more than only a FALSE EYE:

Click Here To Show Diagram Code: [go]$$B ko-shape $$ +---------------+ $$ | . Q . Q . X . | $$ | O O Q X X X . | $$ | X X X X . . . | $$ | . . . . . . . | $$ | . . . . . . . |[/go]

Click Here To Show Diagram Code: [go]$$B false eye $$ +---------------+ $$ | . O M O . X . | $$ | O O O Z X X . | $$ | X X X X . . . | $$ | . . . . . . . | $$ | . . . . . . . |[/go]

------------------------

Click Here To Show Diagram Code: [go]$$B ko-shape $$ +---------------------------+ $$ | . Q O . O . O X X . O . O | $$ | Q X X O O O O X X O O O O | $$ | X X . X X X O X . O O X X | $$ | . . X , X O X X X O O X X | $$ | X X X X X O X . X O X X . | $$ | O O O O X O X X X O X . X | $$ | . . . O O O O O O X X X X | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . |[/go]

Click Here To Show Diagram Code: [go]$$B false eye $$ +---------------------------+ $$ | M O O . O . O X X . O . O | $$ | O Z X O O O O X X O O O O | $$ | X X . X X X O X . O O X X | $$ | . . X , X O X X X O O X X | $$ | X X X X X O X . X O X X . | $$ | O O O O X O X X X O X . X | $$ | . . . O O O O O O X X X X | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . |[/go]

++++++++++++++++++++++++++++++++

Being a FALSE EYE means that the remaining SINGLE-ko shape is equivalent to a single liberty. Please refer to my previous posting for a more detailled explanation.
Honte's magic wand can be applied on these remaining SINGLE-ko, too! Please note that stones in SINGLE-ko will only move AFTER their collegues in the DOUBLE-ko already did. Please also note that in principle the formations that remain on the bord after Honte's magic DOUBLE-ko spell will not be particularly complicated, so in many cases you will be able to recognize the status without further magic.

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | . O Q T . X . | $$ | O O O X X X . | $$ | X X X X . . . | $$ | . . . . . . . | $$ | . . . . . . . |[/go]

After Honte used his magic wand for the second time...

------------------------

Click Here To Show Diagram Code: [go]$$B ko-shape $$ +---------------------------+ $$ | Q O O . O . O X X . O . O | $$ | T X X O O O O X X O O O O | $$ | X X . X X X O X . O O X X | $$ | . . X , X O X X X O O X X | $$ | X X X X X O X . X O X X . | $$ | O O O O X O X X X O X . X | $$ | . . . O O O O O O X X X X | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . |[/go]

After Honte used his magic wand for the second time...

There is NO ko at the beginning of status confirmation!

J89 were trying to fix something that wasn't broken at all.

As we now know (viewtopic.php?p=267061#p267061), there are exceptions...

##### False eyes during play #####

Please note that false eyes have different properties during play.

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | O X X X . O . O X | $$ | O O O O O O O X X | $$ | X X X X X X X X X | $$ | . . . O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Black to move.

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | O X X X 2 O 1 O X | $$ | O O O O O O O X X | $$ | X X X X X X X X X | $$ | . . . O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Click Here To Show Diagram Code: [go]$$Bm3 $$ +-------------------+ $$ | O . 1 5 O O X 3 X | $$ | O O O O O O O X X | $$ | X X X X X X X X X | $$ | O 2 4 6 O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Please note that White's moves are played on the OUTSIDE, which would be irrelevant in status confirmation.

Click Here To Show Diagram Code: [go]$$Bm5 $$ +-------------------+ $$ | O . X X O O . . . | $$ | O O O O O O O . . | $$ | . . . . . . . . . | $$ | O O O O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

White won the semeai.

++++++++++++++++++++++++

Honte's magic SINGLE-ko spell is NOT designed for the real world!

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | O X X X . O Q T X | $$ | O O O O O O O X X | $$ | X X X X X X X X X | $$ | . . . O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Black to move.

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | O X X X 2 O O 1 X | $$ | O O O O O O O X X | $$ | X X X X X X X X X | $$ | . . . O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | O 7 3 5 O O O X X | $$ | O O O O O O O X X | $$ | X X X X X X X X X | $$ | 4 6 . O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Please note that White's moves are played on the OUTSIDE, which would be irrelevant in status confirmation.

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . X X X . . . X X | $$ | . . . . . . . X X | $$ | X X X X X X X X X | $$ | O O . O O O O O O | $$ | O O O O . . . . . | $$ | . . . . . . . . . | $$ | . . . . . . . . . |[/go]

Black won the semeai.

_________________
EDITED

Gérard TAILLE · Post by **Gérard TAILLE** » Mon Aug 30, 2021 2:48 am

Thomas,
Obviously it is still too early to know how to use Honte's magic wand. Surely it will be used during a confirmation phase (normal play is OC excluded) but what kind of confirmation phase? In GT territory rule the confirmation phase is quite close to normal play while in J89 or J2008 the pass-for-ko or the ko-pass change the analyse. In any case I guess magic wand might be use but only in special conditions which will depend of the confirmation phase used.
The best is to wait still a moment isn't it? Later, depending of how works in detail the confirmation phase you have in mind, surely you will be able to define the conditions to use the magic wand : who can use this wand (the attacker, the defender, both), in which kind of position the wand may be used (existing kos, number of groups involved, two stage ko allowed ...) when the wand can be used (remember in GT rule I defined special moment by using "critical" position) ...

Exceptionnaly

I will try to avoid being impatient relating to the use of the Honte's magic. Take all the time needed to progress in your analysis.
Wait and see.

Cassandra · Post by **Cassandra** » Mon Aug 30, 2021 2:55 am

(clicked "Submit" too early here...)

Cassandra · Post by **Cassandra** » Mon Aug 30, 2021 3:13 am

Gérard TAILLE wrote:Thomas,
Obviously it is still too early to know how to use Honte's magic wand. Surely it will be used during a confirmation phase (normal play is OC excluded) but what kind of confirmation phase? In GT territory rule the confirmation phase is quite close to normal play while in J89 or J2008 the pass-for-ko or the ko-pass change the analyse. In any case I guess magic wand might be use but only in special conditions which will depend of the confirmation phase used.
The best is to wait still a moment isn't it? Later, depending of how works in detail the confirmation phase you have in mind, surely you will be able to define the conditions to use the magic wand : who can use this wand (the attacker, the defender, both), in which kind of position the wand may be used (existing kos, number of groups involved, two stage ko allowed ...) when the wand can be used (remember in GT rule I defined special moment by using "critical" position) ...

Exceptionnaly I will try to avoid being impatient relating to the use of the Honte's magic. Take all the time needed to progress in your analysis.
Wait and see.

Analysis:

Is finished as you can see from my previous posting. I am waiting for potential counter-examples.
I still seriously wonder if I am really the very first to discover these principles.

----------------------

Usage:

Final board position of "play" ==> Apply "Honte's Magic Ko Spells" on the entire board ==> Board position for "status confirmation" / "territory identification".

That's all.
The number of potential occasions for controversial discussions remaining will be extremely limited. The same applies to both the occurrence of potential applications of any ko-pass variants and to "pass" after ko-captures.
Regardless of which ruleset you apply, you will always get the "J89-intended" result.

+++++++++++++++++++++++++++++

By the way:
I've heard rumours that Queen rewrote the first two verses of their well-known hit "A Kind of Magic":

No ko, no loop, no capture ban
No golden glance of what could be
It's a kind of magic

One magic spell that shows the way
A Labrador will win this day
It's a kind of magic

___________________
EDITED

Life In 19x19

GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles

Re: GT territory rules:: Honte's loops and cycles