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Offline jlt
 Post subject: Re: Tsumegos from real games
Post #101 Posted: Tue Feb 06, 2024 2:51 am 
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Problem #39, Black to play.

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


Answer:

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . O O O X . . . |
$$ | . O . O O X X . . . . O X . X X . . . |
$$ | . . . O X . . X . X X O X . O X O . . |
$$ | . O O X X X . X O , O O X X O X X . . |
$$ | . O X O O X . X O . O O O X X . X X . |
$$ | . X X X O X X X O . X . X O O X O X X |
$$ | . . . O O O O X O . . . X . . O O O X |
$$ | . X X O X X X O O O X X . X . O X X X |
$$ | X . X O O X X O . . O X . X O O O O O |
$$ | . X O O X X O O O , O X . X . , . O . |
$$ | 4 O . O O X O X O . O X . X O O O X . |
$$ | 5 3 . 2 1 X O X O O X X X O . . O X . |
$$ | . . X O O X X X X O O . . O O O X . . |
$$ | . O O X X . X O X X X X X O X . X . . |
$$ | . O O X . . O O X X O O O X X X . . . |
$$ | . X O O O O O X X O . O X X O O X . . |
$$ | . X X X O X X O O O . . O . O X . . . |
$$ | . . . . X . X X O . . O . O O X . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ ---------------------------------------[/go]
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Offline jlt
 Post subject: Re: Tsumegos from real games
Post #102 Posted: Fri Mar 01, 2024 6:21 am 
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Problem #40, White to play. I've probably seen the problem before, but forgot it.

Click Here To Show Diagram Code
[go]Wc
$$ | . . . O O X . O . O . X
$$ | . . O O X O X . . . . X
$$ | . O . . X O . X X X X .
$$ | . X O O X . O O O O X .
$$ | . X X X O O . . . . O O
$$ | . . . . X X O X . . . .
$$ | . . . . . . O . . . . .
$$ -------------------------[/go]
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Offline dfan
 Post subject: Re: Tsumegos from real games
Post #103 Posted: Sat Mar 02, 2024 12:58 pm 
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Yeah, this one shows up in life and death manuals. I learned it as part of the J-group collection.
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Offline Harleqin
 Post subject: Re: Tsumegos from real games
Post #104 Posted: Sat Mar 02, 2024 6:13 pm 
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I think like this:

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

_________________
A good system naturally covers all corner cases without further effort.

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Offline jlt
 Post subject: Re: Tsumegos from real games
Post #105 Posted: Mon Mar 04, 2024 12:26 am 
Gosei
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Problem #41, Black to live.

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


Answer:

Click Here To Show Diagram Code
[go]$$Bc Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X X O O . . . . . . . X O . . . . |
$$ | . . X O . X O . . . . . X X X O O O . |
$$ | . . X O . . . . . O . . . . O X X O . |
$$ | . . . O . . . . . . . . . . X . . X . |
$$ | . . X X . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , X . . . . , . . . . . , . . . |
$$ | . 6 O O X O . . . . . . . . . O . . . |
$$ | . 3 4 X O O . . . . . . . . . . . . . |
$$ | . O 5 X O X X . . . . . . . O . . . . |
$$ | . 7 X . X O . X . . . . . X O X . . . |
$$ | . . . X 1 O . . . . X . X . X O O . . |
$$ | . X X O 2 . O . X , . O . . X , . . . |
$$ | . X O O . O X . X O . . . O . X X O . |
$$ | . O . . O X . X O O . . . . O O X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
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Offline jlt
 Post subject: Re: Tsumegos from real games
Post #106 Posted: Mon Mar 25, 2024 4:55 am 
Gosei
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Problem #41, Black to kill the upper left corner. Not very difficult but it was a blitz game and I failed completely.

Click Here To Show Diagram Code
[go]$$Bc Black to play.
$$ ---------------------------------------
$$ | . O . . O . . . . . . . . . . . . . . |
$$ | . X O O X X X . . . . X . . . . . . . |
$$ | . X . O O O X X X X . . . . . X O . . |
$$ | . O O X X O X O X O O . . . . X O . . |
$$ | . . X X O X O O O O . . . . . X O . . |
$$ | . X . . O X . . O . O . . . . X X O . |
$$ | . . X . O X X . X O X X X X X O O . . |
$$ | . . X O O X O X X O O O X O O X O . . |
$$ | . X O . . O . O X X O . O . O X O . . |
$$ | . X O , . O O O X X O X . . O X X . . |
$$ | . . X X . . . O X X X O O O O O X X . |
$$ | . . . . . O O X O X . X X O X X O . . |
$$ | . X O . . O X . O X . X X X X O O O O |
$$ | . X O . . . X X O X X X X O O . O X . |
$$ | . X O . . X O X X X O O O . . O X . X |[/go]
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Offline xela
 Post subject: Re: Tsumegos from real games
Post #107 Posted: Mon Mar 25, 2024 3:01 pm 
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Cute!

What I might have done in a blitz game
Click Here To Show Diagram Code
[go]$$Bc Ko
$$ ---------------------------------------
$$ | 5 O . 1 O . . . . . . . . . . . . . . |
$$ | 2 X O O X X X . . . . X . . . . . . . |
$$ | 3 X . O O O X X X X . . . . . X O . . |
$$ | 4 O O X X O X O X O O . . . . X O . . |
$$ | . . X X O X O O O O . . . . . X O . . |
$$ | . X . . O X . . O . O . . . . X X O . |
$$ | . . X . O X X . X O X X X X X O O . . |[/go]


What I can see when I think for a minute
Click Here To Show Diagram Code
[go]$$Bc Black wins the capturing race
$$ ---------------------------------------
$$ | b O . 2 O . . . . . . . . . . . . . . |
$$ | 1 X O O X X X . . . . X . . . . . . . |
$$ | a X 3 O O O X X X X . . . . . X O . . |
$$ | . O O X X O X O X O O . . . . X O . . |
$$ | . . X X O X O O O O . . . . . X O . . |
$$ | . X . . O X . . O . O . . . . X X O . |
$$ | . . X . O X X . X O X X X X X O O . . |[/go]

Two liberties each, but white needs an approach move and can't play either 'a' or 'b' directly, so black wins. If :w2: at :b3: instead, now :b3: at :w2: actually does work.

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Offline mart900
 Post subject: Re: Tsumegos from real games
Post #108 Posted: Tue Mar 26, 2024 9:32 am 
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Not exactly tsumego, but you might find this interesting https://realgoproblems.com/
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Offline xela
 Post subject: Re: Tsumegos from real games
Post #109 Posted: Tue Mar 26, 2024 4:08 pm 
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mart900 wrote:
Not exactly tsumego, but you might find this interesting https://realgoproblems.com/

Discussion in the other thread at https://lifein19x19.com/viewtopic.php?f=9&t=19425
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Offline jlt
 Post subject: Re: Tsumegos from real games
Post #110 Posted: Thu May 30, 2024 2:05 am 
Gosei
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Problem #42, what can White to?

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


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


If Black a then White b and White has a ko to kill black stones in order to survive.
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Offline EricBackus
 Post subject: Re: Tsumegos from real games
Post #111 Posted: Tue Jun 11, 2024 12:16 pm 
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jlt wrote:
Problem #42, what can White to?

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


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


If Black a then White b and White has a ko to kill black stones in order to survive.

If I'm understanding this right, your "Black a then White b" ends up as a multi-step ko that is disadvantageous to white.

Initially I thought that this would be better:
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . 2 3 4 6 . |
$$ | . . O . . . . . . . . . X X O X 5 . . |
$$ | . . O X X . X X X . X X O X O 1 O O . |
$$ | . . . O . X O . O O . . O b X X X X . |
$$ | . . . . . O . O . . . . . . . . . . . |
$$ | . . O O O . . . . . . . . . . . O . . |
$$ | . . X X O X X . X . . . . . . . O . . |
$$ | . . X O X . O X . X . . . . . O . O . |
$$ | . . X O X . X . . X O . . . X X O . . |
$$ | . . . O O O O X X O . . . X O O X . . |
$$ | . . O . O X O O O . . . . . . O X . . |
$$ | . . . . O X . X O . . . . . X O O . . |
$$ | . . X O . X . X O . . . . . . X O . . |
$$ | . . X . . X . O . O . . . . . X O . . |
$$ | . . . . . . . . O X X . . . . X X O . |
$$ | . . . X X X O O X , . . . . . X O O . |
$$ | . . X O O O O X . X . . . X . . X O . |
$$ | . . X . . . O X . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Then 7 captures at 3 to start the ko. But this is also multi-step, and maybe the threat at b doesn't work.

It's interesting to me because I mentally went down several different paths that I thought were better than your solution, only to eventually convince myself that your solution looks better.
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Offline jlt
 Post subject: Re: Tsumegos from real games
Post #112 Posted: Mon Oct 07, 2024 5:57 am 
Gosei
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Problem #43, White to play. Can White kill the group on the left?

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ -------------------
$$ | . . . . . . . . X
$$ | . . . . . . O O O
$$ | . . . . . O O X X
$$ | . . . O . O . X .
$$ | . O O . . O X . O
$$ | . X X O O X X X X
$$ | . . X X X O X O O
$$ | . . . . . O O X .
$$ | . X O X . . O X .
$$ | X O X X . O . X O
$$ | . O X O O O O O X
$$ | . O O O X O X X .
$$ | . . X O X X O X X
$$ | . O O . X O O X O[/go]
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Offline EricBackus
 Post subject: Re: Tsumegos from real games
Post #113 Posted: Mon Oct 07, 2024 2:18 pm 
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jlt wrote:
Problem #43, White to play. Can White kill the group on the left?

My guess: the black group is alive. I thought I found a ko:

Click Here To Show Diagram Code
[go]$$Wc White to play - ko?
$$ -------------------
$$ | . . . . . . . . X
$$ | . . . . . . O O O
$$ | . . . . . O O X X
$$ | . . . O . O . X .
$$ | . O O . . O X . O
$$ | 4 X X O O X X X X
$$ | 3 . X X X O X O O
$$ | . 1 2 . . O O X .
$$ | 5 X O X . . O X .
$$ | X O X X . O . X O
$$ | . O X O O O O O X
$$ | . O O O X O X X .
$$ | . . X O X X O X X
$$ | . O O . X O O X O[/go]


But, oops, doesn't work after all:

Click Here To Show Diagram Code
[go]$$Wc White to play - white fails
$$ -------------------
$$ | . . . . . . . . X
$$ | . . . . . . O O O
$$ | . . . . . O O X X
$$ | . . . O . O . X .
$$ | . O O . . O X . O
$$ | . X X O O X X X X
$$ | 3 4 X X X O X O O
$$ | . 1 2 . . O O X .
$$ | . X O X . . O X .
$$ | X O X X . O . X O
$$ | . O X O O O O O X
$$ | . O O O X O X X .
$$ | . . X O X X O X X
$$ | . O O . X O O X O[/go]
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