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Tsumegos from real games

https://www.lifein19x19.com/viewtopic.php?t=17076

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Re: Tsumegos from real games

Posted: Mon Mar 25, 2024 4:55 am
by jlt
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]

Re: Tsumegos from real games

Posted: Mon Mar 25, 2024 3:01 pm
by xela
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.

Re: Tsumegos from real games

Posted: Tue Mar 26, 2024 9:32 am
by mart900
Not exactly tsumego, but you might find this interesting https://realgoproblems.com/

Re: Tsumegos from real games

Posted: Tue Mar 26, 2024 4:08 pm
by xela
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

Re: Tsumegos from real games

Posted: Thu May 30, 2024 2:05 am
by jlt
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.

Re: Tsumegos from real games

Posted: Tue Jun 11, 2024 12:16 pm
by EricBackus
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.

Re: Tsumegos from real games

Posted: Mon Oct 07, 2024 5:57 am
by jlt
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]

Re: Tsumegos from real games

Posted: Mon Oct 07, 2024 2:18 pm
by EricBackus
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]

Re: Tsumegos from real games

Posted: Wed Oct 09, 2024 1:21 am
by Harleqin
Maybe start here?
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 $$ | 1 . X X X O X O O $$ | . . . . . 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]

Re: Tsumegos from real games

Posted: Thu May 01, 2025 12:13 am
by jlt
Problem #44, White to kill the central group.

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


I modified the position slightly compared to the game to avoid some complication. The problem is not hard but I played a wrong move.

Re: Tsumegos from real games

Posted: Thu May 01, 2025 11:53 am
by kvasir
Is it like this?
Click Here To Show Diagram Code
[go]$$W $$ . . . O . . . . . . .| $$ X . X O . . . . . . .| $$ . . . O . O . . X . .| $$ X . O . . . . . . . .| $$ . X O . O O O . . . .| $$ X O X X 1 X . O . . .| $$ X O X . X 3 X . . . .| $$ . O 2 X X 4 . 5 O . .| $$ O O X X O X X . . . .| $$ X O O O O O O O O . .| $$ . X . O . . . . X . .| $$ . , . . . X . X . . .|[/go]


It does look like white needs to be very careful and play :w3: and :w5: if black tries to get out in the next diagram.
Click Here To Show Diagram Code
[go]$$Bm2 $$ . . . O . . . . . . .| $$ X . X O . . . . . . .| $$ . . . O . O . . X . .| $$ X . O . . . . . . . .| $$ . X O . O O O . . . .| $$ X O X X O X . O 4 . .| $$ X O X . X . X 1 3 . .| $$ . O . X X . . 2 O . .| $$ O O X X O X X . . . .| $$ X O O O O O O O O . .| $$ . X . O . . . . X . .| $$ . , . . . X . X . . .|[/go]

Re: Tsumegos from real games

Posted: Fri May 02, 2025 2:35 am
by jlt
Yes that's correct, however I fail to see why in your second diagram you don't want to play 3 at 4.

Re: Tsumegos from real games

Posted: Fri May 02, 2025 12:24 pm
by kvasir
I think that would leave a ko.
Click Here To Show Diagram Code
[go]$$Wm3 B10 at marked $$ . . . O . . . . . . .| $$ X . X O . . . . . . .| $$ . . . O . O . . X . .| $$ X . O . . . . . . . .| $$ . X O . O O O . . . .| $$ X O X X O # 5 O . . .| $$ X O X . X 3 X X 1 . .| $$ . O 2 X X 6 . 4 O . .| $$ O O X X O X X 7 . . .| $$ X O O O O O O O O . .| $$ . X . O . . . . X . .| $$ . , . . . X . X . . .|[/go]

Click Here To Show Diagram Code
[go]$$Wm7 B10 at marked $$ . . . O . . . . . . .| $$ X . X O . . . . . . .| $$ . . . O . O . . X . .| $$ X . O . . . . . . . .| $$ . X O . O O O . . . .| $$ X O X X O X 3 O . . .| $$ X O X . X @ X X O . .| $$ . O X X X 1 2 X O . .| $$ O O X X O X X . . . .| $$ X O O O O O O O O . .| $$ . X . O . . . . X . .| $$ . , . . . X . X . . .|[/go]

Re: Tsumegos from real games

Posted: Mon May 05, 2025 10:08 am
by jlt
Problem #45, White to play. Not hard, but easy to miss in a fast game.

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

Re: Tsumegos from real games

Posted: Tue May 06, 2025 5:29 pm
by kvasir
I don't think it is "not hard", but maybe it is like this.
Click Here To Show Diagram Code
[go]$$W $$ | . . X O X . . X . , X . . . O , X . X| $$ | O . X X O . . . . . . . . X X . . . .| $$ | 2 O O O O . . . . . . . . . O X X X .| $$ | 3 X X O . . . . . . X . . O . O . O .| $$ | 4 . X X O . . . . X . . O . O O O . .| $$ | X X X . O . . . . X O O . X . O X . .| $$ | . X . O . . . . O O . O O . . , X . .| $$ | 6 7 X O . . O . O X O O X X . X . . .| $$ | 5 X O O . . . X O X X X . . . . . . .| $$ | . 1 . . . . . . . . . . . . . . . . .| $$ +--------------------------------------+[/go]


Which ko doesn't seem all that important but this was the one that looked the biggest to me.

However, if black had one less liberty, then black could be killed in the following diagram.

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


And black can't do this this either way.
Click Here To Show Diagram Code
[go]$$Bm2 $$ | . . X O X . . X . , X . . . O , X . X| $$ | O . X X O . . . . . . . . X X . . . .| $$ | 3 O O O O . . . . . . . . . O X X X .| $$ | O X X O . . . . . . X . . O . O . O .| $$ | O O X X O . . . . X . . O . O O O . .| $$ | X X X . O . . . . X O O . X . O X . .| $$ | . X . O . . . . O O . O O . . , X . .| $$ | O 4 X O . . O . O X O O X X . X . . .| $$ | 2 X O O . . . X O X X X . . . . . . .| $$ | . 1 . . . . . . . . . . . . . . . . .| $$ +--------------------------------------+[/go]
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