L & D for professionals

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ethanb
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Re: L & D for professionals

Post by ethanb »

Cassandra wrote:Preventing White's Sente on the left immediately ...
... will not work, I suppose.
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X . . . . . . . . |
$$ | . . . . . . . . . O X O O . 2 . O X . |
$$ | . . . . . . . . . X O X O . O . O X . |
$$ | . . . , . . . . . , 1 X X O . . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]



... are you sure?

A and B are miai
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X 7 8 . b . 4 . . |
$$ | . . . . . . . . . O X O O a 2 6 O X . |
$$ | . . . . . . . . . X O X O 9 O 5 O X . |
$$ | . . . , . . . . . , 1 X X O 3 . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]


Again
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X 7 8 . b 5 6 . . |
$$ | . . . . . . . . . O X O O a 2 . O X . |
$$ | . . . . . . . . . X O X O 9 O 4 O X . |
$$ | . . . , . . . . . , 1 X X O 3 . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]



Still dead, I think.
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X 4 . 5 . . 6 . . |
$$ | . . . . . . . . . O X O O . 2 . O X . |
$$ | . . . . . . . . . X O X O . O 7 O X . |
$$ | . . . , . . . . . , 1 X X O 3 . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]



This one is seki, but maybe I've got the wrong order of moves for black. Do we know the answer is supposed to be unconditional death?
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X 4 . 5 9 7 8 . . |
$$ | . . . . . . . . . O X O O . 2 . O X . |
$$ | . . . . . . . . . X O X O 0 O 6 O X . |
$$ | . . . , . . . . . , 1 X X O 3 . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
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Cassandra
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Re: L & D for professionals

Post by Cassandra »

ethanb wrote:"@ Cassandra: '... are you sure?'"


Yes.

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X . a 4 b . . . . |
$$ | . . . . . . . . . O X O O a W . O X . |
$$ | . . . . . . . . . X . X O . O . O X . |
$$ | . . . , . . . . . , B X X O B . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

One of the a is an eye and b is the second one.

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . X . . 3 . . . . . |
$$ | . . . . . . . . . O X O O a W . O X . |
$$ | . . . . . . . . . X . X O a O b O X . |
$$ | . . . , . . . . . , B X X O 6 4 X . . |
$$ | . . . . . . . . . X . . X O 5 X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

a and b will become eyes.
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Igo Hatsuyōron #120 (really solved by KataGo)
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cyclops
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Re: L & D for professionals

Post by cyclops »

prokofiev wrote:A few thoughts that are perhaps obvious:

It seems that if you don't play O19, White gets an easy eye:

Click Here To Show Diagram Code
[go]$$Bcm1 Prisoners: W=0, B=0
$$ ---------------------------------------
$$ | . . . . . . . . . , X 2 . 4 . . . . . |
$$ | . . . . . . . . . O X O O . 1 . O X . |
$$ | . . . . . . . . . X O X O . O . O X . |
$$ | . . . , . . . . . , 3 X X O . . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Edit: Nevermind. I had some idea about ignoring M19, but it clearly does not work...


I'm not sure what is wrong with your B1. B5&r19 next in your diagram seems to kill W. Or??
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Joaz Banbeck
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Re: L & D for professionals

Post by Joaz Banbeck »

ethanb wrote:
...
Click Here To Show Diagram Code
[go]$$Bcm1 Ah, tesuji?
$$ ---------------------------------------
$$ | . . . . . . . . . . X 2 . 4 . . . . . |
$$ | . . . . . . . . . O X O O 8 7 1 O X . |
$$ | . . . . . . . . . X O X O 5 O 9 O X . |
$$ | . . . , . . . . . , 3 X X O 6 . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White can resist better with :w6: like this:

Click Here To Show Diagram Code
[go]$$Bcm1 Ah, tesuji?
$$ ---------------------------------------
$$ | . . . . . . . . . . X 2 . 4 . . . . . |
$$ | . . . . . . . . . O X O O . . 1 O X . |
$$ | . . . . . . . . . X O X O 5 O 6 O X . |
$$ | . . . , . . . . . , 3 X X O . . X . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
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Cassandra
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Re: L & D for professionals

Post by Cassandra »

cyclops wrote:I'm not sure what is wrong with your B1. ...


Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . , X . . . . . . . . |
$$ | . . . . . . . . . O X O O . 1 . O X . |
$$ | . . . . . . . . . X O X O M O M O X . |
$$ | . . . , . . . . . , . X Z O . . Z . . |
$$ | . . . . . . . . . X . . X O . X . X . |
$$ | . . . . . . . . . . . . X O . X . . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Black 1 is an interesting spot.

This is the point to make two of White's potential eyes false simultanously. It goes without saying that this stone has to remain on the board to be effective.

Now the right seems to be more interesting than the left.
The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)
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Jordus
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Re: L & D for professionals

Post by Jordus »

If white plays badly :P Ignore Variations....



A more serious try (again ignore variations):

I'm thinking...
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Joaz Banbeck
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Re: L & D for professionals

Post by Joaz Banbeck »

Jordus wrote:
A more serious try ...


White lives like this:

11 O17
12 takes ko
13 M19
14 L16
15 takes ko
16 ( no ko threat )
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Jordus
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Re: L & D for professionals

Post by Jordus »

Joaz Banbeck wrote:
Jordus wrote:
A more serious try ...


White lives like this:

11 O17
12 takes ko
13 M19
14 L16
15 takes ko
16 ( no ko threat )


I disagree with your move 13... white wouldn:t play m19, they would play p17 to protect the 4 stones in atari...
I'm thinking...
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Joaz Banbeck
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Re: L & D for professionals

Post by Joaz Banbeck »

Jordus wrote:
Joaz Banbeck wrote:
Jordus wrote:
A more serious try ...


White lives like this:

11 O17
12 takes ko
13 M19
14 L16
15 takes ko
16 ( no ko threat )


I disagree with your move 13... white wouldn:t play m19, they would play p17 to protect the 4 stones in atari...


As I understand the rules here, the goal is to kill all of the white stones. If the majority get away, then the line is not a solution.
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Re: L & D for professionals

Post by illluck »

@Jordus:

For your more serious try, I think white response to O19 should be O18?
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Cassandra
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Re: L & D for professionals

Post by Cassandra »

@ Jordus:

Even if your sequence would work for Black, you might have only shown that one :w2: (in answer to one :b1: ) does not bring White to life.

There are other :w2: remaining for White. If none of them brings White to life, this one :b1: is the first move of the solution.
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Igo Hatsuyōron #120 (really solved by KataGo)
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