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Which way to live?
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Author:  Bill Spight [ Fri Apr 05, 2013 11:37 am ]
Post subject:  Which way to live?

Well, maybe I can redeem myself. I think I understand this now.

Click Here To Show Diagram Code
[go]$$B This way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . 1 . X X O . O . . .
$$ | . . . . . . . . . . .
$$ ----------------------[/go]


Click Here To Show Diagram Code
[go]$$B Or this way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . 1 . . . . . . . . .
$$ ----------------------[/go]


Black lives in both cases. But which is the better endgame play?

Enjoy!

Author:  Toge [ Fri Apr 05, 2013 12:53 pm ]
Post subject:  Re: Which way to live?

Search tree is ridiculous.


Author:  Splatted [ Fri Apr 05, 2013 1:33 pm ]
Post subject:  Re: Which way to live?

Thanks for this. I'd seen the one move answer before but was at a complete loss trying to work it out. :D

Author:  Phoenix [ Fri Apr 05, 2013 6:09 pm ]
Post subject:  Re: Which way to live?

This is really cool.

This is just one situation, but in general pros are always looking to squeeze the most value out of every stone. I'd heard about how pros study tsumego until they know every way to live, die, and make ko. I've also seen some struggling to make groups live in games when I keep looking at the simple way to live.

But they want to get ahead, and not only live, but live in the best way they possibly can. Fantastic exercise. :D

Author:  jts [ Fri Apr 05, 2013 7:05 pm ]
Post subject:  Re: Which way to live?

Phoenix wrote:

But they want to get ahead, and not only live, but live in the best way they possibly can. Fantastic exercise. :D


In the words of one great sensei: "The unexamined life is not worth living."

Author:  Bill Spight [ Sat Apr 06, 2013 9:30 am ]
Post subject:  Re: Which way to live?

Click Here To Show Diagram Code
[go]$$W This way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 1 X X X O O . . . . .
$$ | 2 X . X X O . O . . .
$$ | . . . . B W C . . . .
$$ ----------------------[/go]


:w1: is sente. Then we can count 5 points for Black and 1 point for White ( :ec: ). (The :bc: stone and :wc: just indicate equity. We do not expect play to go this way. Either Black or White will play hane-connect.)


Click Here To Show Diagram Code
[go]$$W Or this way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 1 X X X O O . . . . .
$$ | 2 . . X X O . O . . .
$$ | . X . . B W C . . . .
$$ ----------------------[/go]


The same goes for this position.

Click Here To Show Diagram Code
[go]$$W This way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . X . X X O . O . . .
$$ | . . . . 1 . . . . . .
$$ ----------------------[/go]


However, it may not be so obvious, but this :w1: is also sente.

Click Here To Show Diagram Code
[go]$$W Or this way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . X . . 1 . . . . . .
$$ ----------------------[/go]


And this is also sente.

Click Here To Show Diagram Code
[go]$$W Black mistake
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 4 X X X O O . . . . .
$$ | 3 5 7 X X O . O . . .
$$ | . X . 2 1 6 . . . . .
$$ ----------------------[/go]


:b2: is a mistake. Because of shortage of liberties, Black cannot play :b6: at 7. :w7: holds Black to one eye.

Click Here To Show Diagram Code
[go]$$W Correct response
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 2 X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . X . 4 1 5 C . . . .
$$ ----------------------[/go]


:b2: is the correct response. Later :b4: is sente. The result is still 5 points for Black and 1 point for White. Which sente to play depends upon the rest of the board.

Click Here To Show Diagram Code
[go]$$W Life?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 2 X X X O O . . . . .
$$ | . X . X X O . O . . .
$$ | . . . . 1 . . . . . .
$$ ----------------------[/go]


Does :b2: make life?

Click Here To Show Diagram Code
[go]$$W Ko
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 2 X X X O O . . . . .
$$ | . X . X X O . O . . .
$$ | 6 5 3 4 1 . . . . . .
$$ ----------------------[/go]


After :b2:, :w3: takes the vital point. :b6: is necessary to prevent Bent Four in the Corner. (This ko is complicated.)

Click Here To Show Diagram Code
[go]$$W Death
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | 5 X . X X O . O . . .
$$ | . 3 4 2 1 . . . . . .
$$ ----------------------[/go]


If :b2:, :w3: is tesuji. Now if :w4:, :b5: kills, because of Black's shortage of liberties.

Click Here To Show Diagram Code
[go]$$W Ko
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 4 X X X O O . . . . .
$$ | . X . X X O . O . . .
$$ | 6 3 5 2 1 . . . . . .
$$ ----------------------[/go]


So Black replies with :b4:. Then :w5: transposes to the same ko as above.

Click Here To Show Diagram Code
[go]$$W Life
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | 5 X X X O O . . . . .
$$ | 6 X . X X O . O . . .
$$ | . . 2 . 1 . C . . . .
$$ ----------------------[/go]


:b2: lives. Later :w5: is sente. The result is 3 points for Black and 1 point for White, 2 points worse for Black than the other way of living.

Click Here To Show Diagram Code
[go]$$B The way to live
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . 1 . . . . . . . . .
$$ ----------------------[/go]


The jump to the 1-2 is the way to live. :)

Author:  Uberdude [ Sun Apr 07, 2013 1:43 pm ]
Post subject:  Re: Which way to live?

This stuff is interesting, but I can't help feeling it is pretty irrelevant to making me play better. For example I lost a tournament game this weekend because I got the following endgame question wrong:

Do you?

    a) save 2 stones (with a few dame nearby)
    b) save 12 stones (with lots of dame nearby)

My plan was b, but then at the last minute I changed my mind and played a. Woops. :scratch: :-?

Author:  ez4u [ Sun Apr 07, 2013 10:54 pm ]
Post subject:  Re: Which way to live?

Bill Spight wrote:
Well, maybe I can redeem myself. I think I understand this now.

Click Here To Show Diagram Code
[go]$$B This way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . 1 . X X O . O . . .
$$ | . . . . . . . . . . .
$$ ----------------------[/go]


Click Here To Show Diagram Code
[go]$$B Or this way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . 1 . . . . . . . . .
$$ ----------------------[/go]


Black lives in both cases. But which is the better endgame play?

Enjoy!

I have a feeling that there is some background (another thread?) that I missed. That's never stopped me before so...

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

If this is the preceding play, then we know that White has given up on the indirect ko that starts with "a". So Black is ko master? Should this alter our evaluation of the outcomes?

Click Here To Show Diagram Code
[go]$$W Why not just kill?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | 3 O . . . . . . . . .
$$ | 1 X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . . . . b . . . . . .
$$ ----------------------[/go]

If the idea is that Black played tenuki after the hane at :w1:, then why connect at :w3: instead of killing with the second hane at "b"?

Author:  Bill Spight [ Mon Apr 08, 2013 1:13 am ]
Post subject:  Re: Which way to live?

ez4u wrote:
Bill Spight wrote:
Well, maybe I can redeem myself. I think I understand this now.

Click Here To Show Diagram Code
[go]$$B This way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . 1 . X X O . O . . .
$$ | . . . . . . . . . . .
$$ ----------------------[/go]


Click Here To Show Diagram Code
[go]$$B Or this way?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | O O . . . . . . . . .
$$ | O X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . 1 . . . . . . . . .
$$ ----------------------[/go]


Black lives in both cases. But which is the better endgame play?

Enjoy!

I have a feeling that there is some background (another thread?) that I missed. That's never stopped me before so...

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

If this is the preceding play, then we know that White has given up on the indirect ko that starts with "a". So Black is ko master? Should this alter our evaluation of the outcomes?

Click Here To Show Diagram Code
[go]$$W Why not just kill?
$$ | . . . . . . . . . . .
$$ | . . . , . . . . . , .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O . . . . . . . .
$$ | 3 O . . . . . . . . .
$$ | 1 X O O . . . . . , .
$$ | . X X X O O . . . . .
$$ | . . . X X O . O . . .
$$ | . . . . b . . . . . .
$$ ----------------------[/go]

If the idea is that Black played tenuki after the hane at :w1:, then why connect at :w3: instead of killing with the second hane at "b"?


The background is that I had an embarrassing hallucination in another thread. :oops: The problem is as given.

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