32. Magicwand (3d) vs. Kirby (1d)

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Numsgil
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Re: 32. Magicwand vs. Kirby

Post by Numsgil »

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | . O . O X X . . . . . . . . . X O . . |
$$ | O X O O . X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X X X X . . . . . O . O . . |
$$ | . . X . O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


So help a newb out here and answer some questions for me :P

As I read it, black has 3 eye liberties (4 eye space = big eye = 5 liberties. Then subtract 2 for white stones already in it). Plus one internal liberty plus one internal ko.

White has 1 eye liberty plus one internal liberty plus one external liberty plus one internal ko.

So the score for the capture race is black 4 + internal ko and white 3 + internal ko. Black has more exclusive liberties, so he is the "favorite".

Question 1: Why are you fighting over the ko when there are still outside liberties to be filled? Isn't a black move at E4 worth more than taking the ko?

Question 2: Black can use the external liberty of white as a ko threat, right? (E4)

Question 3: Not so much a question. But however I read it out, black is at a distinct advantage.

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | 3 O . O X X . . . . . . . . . X O . . |
$$ | O X O O 1 X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X X X X . . . . . O . O . . |
$$ | . 2 X . O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


Then this: when white fills in the internal liberty at 5, it means he gives black a direct ko for his own death.

Click Here To Show Diagram Code
[go]$$Wc 1 ko threat somewhere, 2 answers. 4 ko threat, white ignores
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | . O . O X X . . . . . . . . . X O . . |
$$ | 3 X O O X X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X X X X . . . . . O . O . . |
$$ | 6 O X 5 O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Wc White is in a direct ko for his own death.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | 2 O . O X X . . . . . . . . . X O . . |
$$ | O X O O X X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | . 1 X X O X X X X . . . . . O . O . . |
$$ | X . X O O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


And it's hard to see any ko threat white can muster worth that much. So instead, it ends up like this. White will tennuki. But whenever black wants, he can force the direct ko. So black definitely has the advantage here, since he takes first.

Click Here To Show Diagram Code
[go]$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | 5 O . O X X . . . . . . . . . X O . . |
$$ | O X O O X X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | . 2 X X O X X X X . . . . . O . O . . |
$$ | 1 4 X 3 O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]
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Solomon
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Re: 32. Magicwand vs. Kirby

Post by Solomon »

Numsgil wrote:Question 1: Why are you fighting over the ko when there are still outside liberties to be filled? Isn't a black move at E4 worth more than taking the ko?

Question 2: Black can use the external liberty of white as a ko threat, right? (E4)

Both of these questions can be answered simultaneously. If Black plays E4, then White will just fill the ko and it becomes seki. Actually it's not seki, but it's fake seki because the E10 group is pretty much dead, so E4 really does nothing.
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Re: 32. Magicwand vs. Kirby

Post by Numsgil »

Araban wrote:
Numsgil wrote:Question 1: Why are you fighting over the ko when there are still outside liberties to be filled? Isn't a black move at E4 worth more than taking the ko?

Question 2: Black can use the external liberty of white as a ko threat, right? (E4)

Both of these questions can be answered simultaneously. If Black plays E4, then White will just fill the ko and it becomes seki. Actually it's not seki, but it's fake seki because the E10 group is pretty much dead, so E4 really does nothing.


Oh, I see now. If it goes E4->connect ko->black D1 then white can capture black's group because of a shortage of liberties.

Always miss those :P
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Re: 32. Magicwand vs. Kirby

Post by Bill Spight »

Click Here To Show Diagram Code
[go]$$Wcm86
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . . X O . . . . . X . X . O . X . . . |
$$ | . . O . . . . . . . X O O . X . . . . |
$$ | . . . . . . . . . O O X . O . . . . . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . a . X X . O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . . . . . . . . . . . X O . |
$$ | X X O X X X . X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | X O . O . X . . . . . . . . . X O . . |
$$ | 1 X O O . X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X . . . . . . . . O . O . . |
$$ | . . X . O . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


This is an interesting ko. Just looking at the corner, it has the potential of becoming a 10,000 year ko. Black has approach moves before that happens, however. It is complicated by the fact that the Black stones on the left side might die. If Black captures all the White stones in the corner, then those stones live. OTOH, if White lives in the corner by making a local seki, then if those Black stones die, the seki becomes a false seki and the Black stones in the corner die. Conversely, if those Black stones die locally, the only hope to save them is to capture the White stones in the corner. If they live, then the corner ko is smaller.

This interdependence between the corner and the side raises the tricky question of which it is better to play in. My feeling at the time was that the fight in the side and center should come first. However, because of the interdependence, I could not say so definitively. Yesterday I experimented with some interdependent positions with fewer Black stones at stake on the side. Even in such a position it was better for each player to play on the side first.

So in this position I think that White should leave the ko and attack the Black group on the side. Perhaps the best play is one he made later, at "a", to take away Black's eye potential there.

What about the corner if Black is alive on the side? There is a saying in go that a three move approach ko is no ko. To kill White Black has to make four approach moves. After that there will be an enormous ko which White takes first. Even if Black can win that ko, playing an approach move is only a large endgame move. A more practical goal is seki, and then playing an approach move is a middle endgame move.
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Re: 32. Magicwand vs. Kirby

Post by Bill Spight »

Numsgil wrote:
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | . O . O X X . . . . . . . . . X O . . |
$$ | O X O O . X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X X X X . . . . . O . O . . |
$$ | . a X . O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


So help a newb out here and answer some questions for me :P

As I read it, black has 3 eye liberties (4 eye space = big eye = 5 liberties. Then subtract 2 for white stones already in it). Plus one internal liberty plus one internal ko.


Black has 1 liberty in the eye, at "a".

White has 1 eye liberty plus one internal liberty plus one external liberty plus one internal ko.

So the score for the capture race is black 4 + internal ko and white 3 + internal ko. Black has more exclusive liberties, so he is the "favorite".


As Araban has pointed out, White can live by filling the ko. Even if the Black stones one the side were alive, there is no such thing as the capturing race in the corner. Either player can aim for seki. In such a case Black can make a kind of 10,000 year ko by filling in White's outside liberty.

Question 1: Why are you fighting over the ko when there are still outside liberties to be filled? Isn't a black move at E4 worth more than taking the ko?


Just looking at the corner, if Black wants to capture the White stones he has to take the ko first to prevent White from making seki.


Question 2: Black can use the external liberty of white as a ko threat, right? (E4)


No. How would White reply to it?

Question 3: Not so much a question. But however I read it out, black is at a distinct advantage.

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | 3 O . O X X . . . . . . . . . X O . . |
$$ | O X O O 1 X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X X X X . . . . . O . O . . |
$$ | . 2 X . O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


:w2: is a mistake. As it is, Black has one liberty in the eye.

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | . O . O X X . . . . . . . . . X O . . |
$$ | O X O O 1 X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | O O X X O X X X X . . . . . O . O . . |
$$ | 3 2 X . O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b3: should just take.

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . X . . . . . . . . . . . |
$$ | . X X O . . . . O X . X X O . X . . . |
$$ | . O O . . . . . . . X O O O X . . . . |
$$ | . . . . . . . . . O O . O O . . . . . |
$$ | . . . . . . . . . . . O X . . . . . . |
$$ | . . . . . . . . . . . X O . . . . . . |
$$ | . . O . . . O . . . . . . . . . . . . |
$$ | . O . X X X O . . , . . . . . , . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . X X O O . O . . . . . . . . . X O . |
$$ | X X O X X X X X . . . . . . . . X O . |
$$ | O O O O O O X . . . . . . . . X O . . |
$$ | . O . O X X . . . . . . . . . X O . . |
$$ | O X O O X X . . . X . . . . . X . O . |
$$ | X X X O O X . . . . . . . X . X O . . |
$$ | . 4 X X O X X X X . . . . . O . O . . |
$$ | X . X . O O O O X . . . . . . . . . . |
$$ ---------------------------------------[/go]


After :w4: Black has 2 liberties in the eye. White has spent one move to give Black a liberty. :)
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.
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