Life In 19x19 :: Tsumegos from real games

Now white is alive and there is no ko.

Click Here To Show Diagram Code: [go]$$Bc Exercise for the reader - white to live $$ | . . . , . . . . . , . . . O X X X X . | $$ | . X X X . . O . . . . . . O O X X . . | $$ | . X O X O X . X X . . . . . . X . X . | $$ | . O O O X X . O X . X X O . O O X . . | $$ | . . . . . . . O X O . . . . . . X . . | $$ | . . . . X . X X O X X X X . O O X . . | $$ | . . O O O . . . O O O O . X X X X . . | $$ | . . X X O O O O . . . . . . . X O O . | $$ | . . . . X X X O . . . . . . X O . 2 1 | $$ | . . . . . . . . . . . . . . 3 . O . . | $$ ---------------------------------------[/go]

Although also it requires the marked spots to be free of black stones:

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

To also prevent this sequence:

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

Anyways, this means that the following push is very bad for white, because white's corner goes from alive to black being able to make a ko.

Click Here To Show Diagram Code: [go]$$Wc bad push $$ | . . . , . . . . . , . . . O X X X X . | $$ | . X X X . . O . . . . . . O O X X . . | $$ | . X O X O X . X X . . . . . . X . X . | $$ | . O O O X X . O X . X X O . O O X . . | $$ | . . . . . . . O X O . . . . . . X . . | $$ | . . . . X . X X O X X X X . O O X 2 . | $$ | . . O O O . . . O O O O . X X X X 1 . | $$ | . . X X O O O O . . . . . . . X O O . | $$ | . . . . X X X O . . . . . . X O . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ ---------------------------------------[/go]

Author:	Harleqin [ Fri Nov 20, 2020 2:19 pm ]
Post subject:	Re: Tsumegos from real games
Q18 seems to make miai.

Author:	jlt [ Wed Dec 09, 2020 7:45 am ]
Post subject:	Re: Tsumegos from real games
Problem #12, Black to play. It seems that Black can kill and that both players (1k Tygem) missed that during all the game. Click Here To Show Diagram Code [go]$$Bc Black to play $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . O . . . . . . . . . O . . . . . \| $$ \| . . . , O . . . . , . . . . . X . . . \| $$ \| . . X . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . X . . . . . . . . . . . . . . . . \| $$ \| . . . O . . . . . . . . . . . . . . . \| $$ \| . . O , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . O . . . . . . . . . . . \| $$ \| . . . . . . . O X . . . . . . . . . . \| $$ \| . . O . . . . O X . . . . . . . . . . \| $$ \| . O O . . . . O X . X X X . . . X . . \| $$ \| . X X O O O O X X , O . O X . , . . . \| $$ \| X . . X O X X O . O . . O O X X . . . \| $$ \| . X X X X X . O . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Answer: Click Here To Show Diagram Code [go]$$Bc $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . O . . . . . . . . . O . . . . . \| $$ \| . . . , O . . . . , . . . . . X . . . \| $$ \| . . X . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . X . . . . . . . . . . . . . . . . \| $$ \| . . . O . . . . . . . . . . . . . . . \| $$ \| . . O , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . O . . . . . . . . . . . \| $$ \| . . . . . . . O X . . . . . . . . . . \| $$ \| . . O . . . . O X . . . . . . . . . . \| $$ \| . O O . . . . O X . X X X . . . X . . \| $$ \| . X X O O O O X X , O 1 O X . , . . . \| $$ \| X . . X O X X O . O . 2 O O X X . . . \| $$ \| . X X X X X . O . . 3 . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go]

Author:	jlt [ Fri Dec 11, 2020 10:48 am ]
Post subject:	Re: Tsumegos from real games
Problem #13: Black to play and kill the bottom group. Click Here To Show Diagram Code [go]$$Bc Black to play $$ --------------------------------------- $$ \| . . . X . . . . . . . . . X O O . O . \| $$ \| . . X O O O . . O X . . . X O . O O X \| $$ \| . . X O . . O X O . X . . X X O O X . \| $$ \| . . O X O O . O . , . . . X X X X . X \| $$ \| . . X X . . . . . X O . O X O . . X . \| $$ \| . . . X X X O . . . . O X O O . . . . \| $$ \| . . X O O O X X X . O . X X . O X . . \| $$ \| . X . X . X O X . O O X X . . O . O . \| $$ \| . O X X X O O X X X O O X . . . O . . \| $$ \| . . O O O O . O X X O . O X . , . . . \| $$ \| . . . . . . . O O X X O O X . . . . . \| $$ \| . . . . O X X X O O O . O X . . O . . \| $$ \| . . O . . O . . X O O . O X . . O O . \| $$ \| . . . . . O X . X X O O X . X X O X . \| $$ \| . . . . . O X . . O X X X X . . X X . \| $$ \| . . . O O X . . . O . . . . X X O O . \| $$ \| . O O X X X . . X . O X X O . X . . . \| $$ \| . . X . . . . . X O . O O . O X X . . \| $$ \| . . . . . . . . O . . . . . . O . . . \| $$ ---------------------------------------[/go] Answer: Click Here To Show Diagram Code [go]$$Bc Answer $$ --------------------------------------- $$ \| . . . X . . . . . . . . . X O O . O . \| $$ \| . . X O O O . . O X . . . X O . O O X \| $$ \| . . X O . . O X O . X . . X X O O X . \| $$ \| . . O X O O . O . , . . . X X X X . X \| $$ \| . . X X . . . . . X O . O X O . . X . \| $$ \| . . . X X X O . . . . O X O O . . . . \| $$ \| . . X O O O X X X . O . X X . O X . . \| $$ \| . X . X . X O X . O O X X . . O . O . \| $$ \| . O X X X O O X X X O O X . . . O . . \| $$ \| . . O O O O . O X X O . O X . , . . . \| $$ \| . . . . . . . O O X X O O X . . . . . \| $$ \| . . . . O X X X O O O . O X . . O . . \| $$ \| . . O . . O . . X O O . O X . . O O . \| $$ \| . . . . . O X . X X O O X . X X O X . \| $$ \| . . . . . O X . . O X X X X . . X X . \| $$ \| . . . O O X . . . O . . . . X X O O . \| $$ \| . O O X X X . . X 1 O X X O . X . . . \| $$ \| . . X . . . . . X O . O O . O X X . . \| $$ \| . . . . . . . . O . . . . . . O . . . \| $$ ---------------------------------------[/go]

Author:	jlt [ Mon Jan 11, 2021 1:35 am ]
Post subject:	Re: Tsumegos from real games
This ridiculous position is from a blitz game. Problem #14: Black to play. Which group should Black choose to kill and how? Click Here To Show Diagram Code [go]$$Bc Black to play $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . X . . . \| $$ \| . . O . . . . . . . . O . . X . X O . \| $$ \| . X X O O O . . . . . . . X X . X O . \| $$ \| . . . X X X O O O O . O . . . X O O . \| $$ \| . . . . . . X X X O . . . . . X X O . \| $$ \| . . . . . . . . . . . . . . . X O O . \| $$ \| . . . . . X . . X . . . . . . . X . . \| $$ \| . . . . . X O . . . . . . . . . . . . \| $$ \| . . . X X O . . . X . . . . O O . . . \| $$ \| . . X O O . O . O O X . . X O X . . . \| $$ \| . . . . . . . . . . X . X X X O O . . \| $$ \| . . X . . . O . . O X X O O X X O . . \| $$ \| . . . . X O O . . . X O O . O X O . . \| $$ \| . . . . . X O X . . X O . O . X . . . \| $$ \| . . X X . X X . . . X . . . . X O . . \| $$ \| . . O , . O . . . , X O . O O X O . . \| $$ \| . . . O . . . O . . X . O . X X O . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Answer: Click Here To Show Diagram Code [go]$$Bc Answer $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . X . . . \| $$ \| . . O . . . . . . . . O . . X . X O . \| $$ \| . X X O O O . . . . . . . X X . X O . \| $$ \| . . . X X X O O O O . O . . . X O O . \| $$ \| . . . . . . X X X O . . . . . X X O . \| $$ \| . . . . . . . . . . . . . . . X O O . \| $$ \| . . . . . X . . X . . . . . . . X . . \| $$ \| . . . . . X O . . . . . . . . . . . . \| $$ \| . . . X X O . . . X . . . . O O . . . \| $$ \| . . X O O . O . O O X . . X O X . . . \| $$ \| . . . . . a . . . . X . X X X O O . . \| $$ \| . . X . . . O . . O X X O O X X O . . \| $$ \| . . . . X O O . . . X O O . O X O . . \| $$ \| . . . . . X O X . . X O . O . X . . . \| $$ \| . . X X . X X . . . X . b . . X O . . \| $$ \| . . O , . O . . . , X O . O O X O . . \| $$ \| . . . O . . . O . . X . O . X X O . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] "a" kills a bigger group than "b".

Author:	jlt [ Sun Jan 17, 2021 9:35 am ]
Post subject:	Re: Tsumegos from real games
Problem #15: Black to play. What is the status of the lower right corner? Click Here To Show Diagram Code [go]$$Bc $$ --------------------------------------- $$ \| . . . . . . . . . . . O X X . . X . . \| $$ \| . . . O . O . . . . . O O X O O X . . \| $$ \| . . O , . . . . O , O X X . X X . . . \| $$ \| . O X X . . O . . . O . O X X . . . . \| $$ \| . O O X . X X X . . . . O X . X . . . \| $$ \| . O X X . . O X . . X O . O X X O . . \| $$ \| . O O X . . O . X . . O O O O O . O . \| $$ \| . . . X . . . O O O . . O X X X O O . \| $$ \| . . . , . . . . . , . . . O X X X X . \| $$ \| . X X X . . O . . . . . . O O X X . . \| $$ \| . X O X O X . X X . . . . . . X O O X \| $$ \| . O O O X X . O X . X X O . O O X X . \| $$ \| . . . . . . . O X O . . . . . . X X . \| $$ \| . . . . X . X X O X X X X . O O O X . \| $$ \| . . O O O . . . O O O O . X X X X O . \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . . . \| $$ \| . . . . . . . . . . . . . . . . O . . \| $$ ---------------------------------------[/go] Click Here To Show Diagram Code `[go]$$Bc Ko $$ \| . X O X O X . X X . . . . . . X O O X \| $$ \| . O O O X X . O X . X X O . O O X X . \| $$ \| . . . . . . . O X O . . . . . . X X . \| $$ \| . . . . X . X X O X X X X . O O O X . \| $$ \| . . O O O . . . O O O O . X X X X O . \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . 2 1 \| $$ \| . . . . . . . . . . . . . . 3 . O . . \| $$ ---------------------------------------[/go]`

Life In 19x19 http://www.lifein19x19.com/

Tsumegos from real games http://www.lifein19x19.com/viewtopic.php?f=15&t=17076	Page 3 of 4

Author:	jlt [ Sat Jan 30, 2021 10:22 am ]
Post subject:	Re: Tsumegos from real games
Problem #16, Black to play. I was white playing an H9 game and killed the upper left corner. However, Black could have lived. How? Click Here To Show Diagram Code [go]$$Bc Black to play $$ --------------------------------------- $$ \| . . . . . . . . O O X . . . . . . . . \| $$ \| . O O . X X O . O X X . . . . . . . . \| $$ \| X X X . X O . O X . . . . . X O O . . \| $$ \| . O O X X O . . . X . . . X . X X O . \| $$ \| O . . O X O . O X . . . . . . . X O . \| $$ \| . O . . O X . O X . . . . . . X X X O \| $$ \| . O . O O X . O X X . . . . . . X O . \| $$ \| O . O . O . . O X . . . . . . . X O . \| $$ \| . O X O . O . . O O X X . X . . X O . \| $$ \| . X . X . . . . . X O X X O . X O . . \| $$ \| . . X . . O . . . . O . O O X X O . . \| $$ \| . . . . . O . X X . . O . . X O . . . \| $$ \| . . . . X O X . O O O X X . X O O . . \| $$ \| . . X . X X O . O X X . . . . X O . . \| $$ \| . . . . X O O . X . . . . . . X X O . \| $$ \| . . X X . . . . . X . . . X . X O . . \| $$ \| . . X O . O . . O X . . . . . X O . . \| $$ \| X X O O . . . . O X . . . . X O O . . \| $$ \| . O . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go]

Author:	lightvector [ Sat Jan 30, 2021 11:42 am ]
Post subject:	Re: Tsumegos from real games
About problem 15 shape, one interesting thing to know, if we adjust the stones a little... Click Here To Show Diagram Code [go]$$Bc White status? $$ \| . . . , . . . . . , . . . O X X X X . \| $$ \| . X X X . . O . . . . . . O O X X . . \| $$ \| . X O X O X . X X . . . . . . X . X . \| $$ \| . O O O X X . O X . X X O . O O X . . \| $$ \| . . . . . . . O X O . . . . . . X . . \| $$ \| . . . . X . X X O X X X X . O O X . . \| $$ \| . . O O O . . . O O O O . X X X X . . \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . . . \| $$ \| . . . . . . . . . . . . . . . . O . . \| $$ ---------------------------------------[/go] Now white is alive and there is no ko. Click Here To Show Diagram Code [go]$$Bc Exercise for the reader - white to live $$ \| . . . , . . . . . , . . . O X X X X . \| $$ \| . X X X . . O . . . . . . O O X X . . \| $$ \| . X O X O X . X X . . . . . . X . X . \| $$ \| . O O O X X . O X . X X O . O O X . . \| $$ \| . . . . . . . O X O . . . . . . X . . \| $$ \| . . . . X . X X O X X X X . O O X . . \| $$ \| . . O O O . . . O O O O . X X X X . . \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . 2 1 \| $$ \| . . . . . . . . . . . . . . 3 . O . . \| $$ ---------------------------------------[/go] Although also it requires the marked spots to be free of black stones: Click Here To Show Diagram Code [go]$$Bc $$ \| . . . , . . . . . , . . . O X X X X . \| $$ \| . X X X . . O . . . . . . O O X X . . \| $$ \| . X O X O X . X X . . . . . . X . X . \| $$ \| . O O O X X . O X . X X O . O O X C . \| $$ \| . . . . . . . O X O . . . . . . X C . \| $$ \| . . . . X . X X O X X X X . O O X C . \| $$ \| . . O O O . . . O O O O . X X X X . . \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . . . \| $$ \| . . . . . . . . . . . . . . . . O . . \| $$ ---------------------------------------[/go] To also prevent this sequence: Click Here To Show Diagram Code [go]$$Bc $$ \| . . . , . . . . . , . . . O X X X X . \| $$ \| . X X X . . O . . . . . . O O X X . . \| $$ \| . X O X O X . X X . . . . . . X . X . \| $$ \| . O O O X X . O X . X X O . O O X C . \| $$ \| . . . . . . . O X O . . . . . . X C . \| $$ \| . . . . X . X X O X X X X . O O X C . \| $$ \| . . O O O . . . O O O O . X X X X 4 5 \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . 1 2 \| $$ \| . . . . . . . . . . . . . . . . O 3 . \| $$ ---------------------------------------[/go] Anyways, this means that the following push is very bad for white, because white's corner goes from alive to black being able to make a ko. Click Here To Show Diagram Code [go]$$Wc bad push $$ \| . . . , . . . . . , . . . O X X X X . \| $$ \| . X X X . . O . . . . . . O O X X . . \| $$ \| . X O X O X . X X . . . . . . X . X . \| $$ \| . O O O X X . O X . X X O . O O X . . \| $$ \| . . . . . . . O X O . . . . . . X . . \| $$ \| . . . . X . X X O X X X X . O O X 2 . \| $$ \| . . O O O . . . O O O O . X X X X 1 . \| $$ \| . . X X O O O O . . . . . . . X O O . \| $$ \| . . . . X X X O . . . . . . X O . . . \| $$ \| . . . . . . . . . . . . . . . . O . . \| $$ ---------------------------------------[/go]

Author:	jlt [ Sat Jan 30, 2021 3:44 pm ]
Post subject:	Re: Tsumegos from real games
In fact you make me realize that Problem #15 is the tripod group with extra leg. https://senseis.xmp.net/?TripodGroupWithExtraLeg I had read this page before, but not carefully.

Author:	jlt [ Mon Feb 01, 2021 12:32 am ]
Post subject:	Re: Tsumegos from real games
Answer to problem #16: Click Here To Show Diagram Code `[go]$$Bc Answer $$ ------------------------- $$ \| . 8 9 . 3 2 1 . O O X . $$ \| 5 O O 6 X X O 4 O X X . $$ \| X X X 7 X O . O X . . . $$ \| . O O X X O . . . X . . $$ \| O . . O X O . O X . . . $$ \| . O . . O X . O X . . .[/go]`

Author:	jlt [ Sat Feb 06, 2021 2:24 pm ]
Post subject:	Re: Tsumegos from real games
Problem #17, White to play. What is the status of the black group Q7? Click Here To Show Diagram Code [go]$$Wc White to play $$ --------------------------------------- $$ \| . X . . . . . . . . . . . . . . . . . \| $$ \| O X O O . . . . . . . . . . . . . . . \| $$ \| . O X O . . . . . . . O X X X . . . . \| $$ \| O X X O . . . . X O . O X O . , X . . \| $$ \| X X X O . . . O O . O X O O O X . X . \| $$ \| . X O O . . . . . X . X X X O O X . . \| $$ \| . . X . . . . . . . . X . X . O O . . \| $$ \| . X . . . . . . X . X . X . X X O . . \| $$ \| . . . . . . . . . . X X O O O O O . . \| $$ \| . . O , . . . O . O X O O X . , . . . \| $$ \| . . . . . . . . . . O O X . X . X . . \| $$ \| . . . . . . . . . O O . O . . . . . . \| $$ \| . . . . . . . . . . X O . X . X X . . \| $$ \| . . . O . . . . . . . . O . X . X O . \| $$ \| . O O . . . . X X . . . . . . X O . O \| $$ \| . X X O . . . O . X . O . O O O O O . \| $$ \| . . X O . O . . . . X O . O X X X . . \| $$ \| X . X X O . . . . . . X X X . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Answer ? This seems to be a ko. Click Here To Show Diagram Code [go]$$Wc $$ --------------------------------------- $$ \| . X . . . . . . . . . . . . . . . . . \| $$ \| O X O O . . . . . . . . . . . . . . . \| $$ \| . O X O . . . . . . . O X X X . . . . \| $$ \| O X X O . . . . X O . O X O . , X . . \| $$ \| X X X O . . . O O . O X O O O X . X . \| $$ \| . X O O . . . . . X . X X X O O X . . \| $$ \| . . X . . . . . . . . X . X . O O . . \| $$ \| . X . . . . . . X . X . X . X X O . . \| $$ \| . . . . . . . . . . X X O O O O O . . \| $$ \| . . O , . . . O . O X O O X . , . b . \| $$ \| . . . . . . . . . . O O X . X . X . . \| $$ \| . . . . . . . . . O O . O 1 2 . . a . \| $$ \| . . . . . . . . . . X O . X . X X . . \| $$ \| . . . O . . . . . . . . O . X . X O . \| $$ \| . O O . . . . X X . . . . . 3 X O . O \| $$ \| . X X O . . . O . X . O . O O O O O . \| $$ \| . . X O . O . . . . X O . O X X X . . \| $$ \| X . X X O . . . . . . X X X . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] a and b are miai.

Author:	jlt [ Sun Apr 11, 2021 7:28 am ]
Post subject:	Re: Tsumegos from real games
An easy one, that both players missed. Problem#18, White to play in the lower left corner. Click Here To Show Diagram Code `[go]$$Wc $$ \| . . . . . . . . . . . . . $$ \| . . . . . . . O . . X . X $$ \| . . . . . . . . . O . . . $$ \| . X X X . . . O . . . . . $$ \| . . O X . X . X O . O O O $$ \| . O O , . . X . O O X X X $$ \| . X . O . O X O O X X O O $$ \| . . X . . O O X X X . X X $$ \| . . . . . . . . . . X . . $$ ---------------------------[/go]` Wrong answer: Click Here To Show Diagram Code `[go]$$Wc ko $$ \| . . . . . . . . . . . . . $$ \| . . . . . . . O . . X . X $$ \| . . . . . . . . . O . . . $$ \| . X X X . . . O . . . . . $$ \| 5 6 O X . X . X O . O O O $$ \| 4 O O , . . X . O O X X X $$ \| . X . O . O X O O X X O O $$ \| 2 . X 1 . O O X X X . X X $$ \| . 3 . . . . . . . . X . . $$ ---------------------------[/go]` Correct answer: Click Here To Show Diagram Code `[go]$$Wc Black is unconditionally dead $$ \| . . . . . . . . . . . . . $$ \| . . . . . . . O . . X . X $$ \| . . . . . . . . . O . . . $$ \| . X X X . . . O . . . . . $$ \| . . O X . X . X O . O O O $$ \| 1 O O , . . X . O O X X X $$ \| . X . O . O X O O X X O O $$ \| . . X 2 3 O O X X X . X X $$ \| . . . . . . . . . . X . . $$ ---------------------------[/go]`

Author:	jlt [ Wed Apr 14, 2021 12:02 pm ]
Post subject:	Re: Tsumegos from real games
Problem#19: not complicated but not my first instinct. White to play. Click Here To Show Diagram Code `[go]$$Wc White to play $$--------------------- $$ . . . . . . . . . . \| $$ . X X O . . . . . . \| $$ . X O . O . X X X . \| $$ , X O . X . O X O . \| $$ . . O . . . O O . . \| $$ X . . . . . . O . . \| $$ . . . . . . O . O . \| $$ . . . . . . . O X . \| $$ . . . . . . . X . . \| $$ , . . . . . , . . . \| $$ . . . . . . . X . . \|[/go]`

Author:	Knotwilg [ Thu Apr 15, 2021 2:20 am ]
Post subject:	Re: Tsumegos from real games
Click Here To Show Diagram Code `[go]$$Wc White to play $$--------------------- $$ . . . . . . 9 6 3 . \| $$ . X X O . 1 . 7 8 a \| $$ . X O . O . X X X . \| $$ , X O . X . O X O 4 \| $$ . . O . . . O O 2 b \| $$ X . . . . . . O . 5 \| $$ . . . . . . O . O . \| $$ . . . . . . . O X . \| $$ . . . . . . . X . . \| $$ , . . . . . , . . . \| $$ . . . . . . . X . . \|[/go]`

Author:	jlt [ Tue Jun 01, 2021 7:59 am ]
Post subject:	Re: Tsumegos from real games
Problem #20: this one is easy but I hallucinated during the game. White to play. Click Here To Show Diagram Code [go]$$Wc White to play $$ --------------------------------------- $$ \| . . . . . . . . . . O . . . . . . . . \| $$ \| . . . . O X . . . O X O O O O . . O O \| $$ \| . O X O . . . X O O X X X X X O O X . \| $$ \| . O X O . . X . O X X . . . X X X X . \| $$ \| . X O O X X . . O O . . O O O X . . X \| $$ \| X . X O O O X X . . . . . O X X . X . \| $$ \| . X . X O . O X . O . . . . . . O X . \| $$ \| . . . X . . O X X O . . . O . . O O . \| $$ \| . . . . . . O . . X O O . . . O . . . \| $$ \| . . . , . . . . X , X . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . X . . . . . . . . . . . . X X . . \| $$ \| . . . . . . . . . . . . . . X . . X . \| $$ \| . . . . . . . . . . . . . . . . O O . \| $$ \| . . X . . . . . . . O . . . . X O . . \| $$ \| . . . , O . . . . , . X . . . X O . . \| $$ \| . X X O . . . O . X . . . . . X O . . \| $$ \| . . O . . . . . X . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Answer: Click Here To Show Diagram Code [go]$$Wc Answer $$ --------------------------------------- $$ \| . . . . . . . . . . O . . . . . . . . \| $$ \| . . . . O X . . . O X O O O O . . O O \| $$ \| . O X O . . . X O O X X X X X O O X 1 \| $$ \| . O X O . . X . O X X . . . X X X X 5 \| $$ \| . X O O X X . . O O . . O O O X 4 . X \| $$ \| X . X O O O X X . . . . . O X X 3 X . \| $$ \| . X . X O . O X . O . . . . . . O X 2 \| $$ \| . . . X . . O X X O . . . O . . O O . \| $$ \| . . . . . . O . . X O O . . . O . . . \| $$ \| . . . , . . . . X , X . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . X . . . . . . . . . . . . X X . . \| $$ \| . . . . . . . . . . . . . . X . . X . \| $$ \| . . . . . . . . . . . . . . . . O O . \| $$ \| . . X . . . . . . . O . . . . X O . . \| $$ \| . . . , O . . . . , . X . . . X O . . \| $$ \| . X X O . . . O . X . . . . . X O . . \| $$ \| . . O . . . . . X . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] and may be interchanged. Yes after several years of practice I still make confusions between real eyes and false eyes.

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Author:	jlt [ Thu Jun 03, 2021 2:37 am ]
Post subject:	Re: Tsumegos from real games
Problem #21: White to play. Killing is not very hard but White needs to pay attention to something. Click Here To Show Diagram Code [go]$$Wc White to play $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . O O . . . . . . . . . . . . O O O . \| $$ \| . X O . . . O O X . X O O . O X O X X \| $$ \| . X X O O O . X X , X O X . . X X X . \| $$ \| . . . X . . . . X . X X O O O . . . X \| $$ \| . . X . X X X . O X O O X X O X X X . \| $$ \| . . . . . O . . . . . X . . . O O X O \| $$ \| . . O . O . . O . O O X O . O . O O . \| $$ \| . O . O . O . . . O X X . . O X O X . \| $$ \| O . O X O X O O X X . . . O . X X . . \| $$ \| . O X X O X . X . . . . . . . . . X . \| $$ \| . . . . O X . X . X . X X O O X . . . \| $$ \| . . . X X O . . . X . . O X . X O . . \| $$ \| . . . . X O O . . O X . O X . X O . . \| $$ \| . . . . . X O . . O X . O . . . O . . \| $$ \| . . X , . X O . O X . . . O . , . . . \| $$ \| . . . X . X O . O X X . X . . O . . . \| $$ \| . . . . X O O . O O X . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Answer: R8. The point is that Black loses the following capturing race: Click Here To Show Diagram Code [go]$$Wc Answer $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . O O . . . . . . . . . . . . O O O . \| $$ \| . X O . . . O O X . X O O . O X O X X \| $$ \| . X X O O O . X X , X O X . . X X X . \| $$ \| . . . X . . . . X . X X O O O . . . X \| $$ \| . . X . X X X . O X O O X X O X X X . \| $$ \| . . . . . O . . . . . X . . . O O X O \| $$ \| . . O . O . . O . O O X O . O . O O . \| $$ \| . O . O . O . . . O X X . . O X O X . \| $$ \| O . O X O X O O X X . . . O . X X . . \| $$ \| . O X X O X . X . . . . . . . . . X . \| $$ \| . . . . O X . X . X . X X O O X 1 . . \| $$ \| . . . X X O . . . X . . O X . X O . . \| $$ \| . . . . X O O . . O X . O X . X O . . \| $$ \| . . . . . X O . . O X . O 6 0 9 O . . \| $$ \| . . X , . X O . O X . . 7 O 2 4 5 . . \| $$ \| . . . X . X O . O X X . X 8 3 O . . . \| $$ \| . . . . X O O . O O X . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] and then P7 is a connect-and-die.

Author:	jlt [ Fri Jun 11, 2021 3:24 am ]
Post subject:	Re: Tsumegos from real games
Problem #22, White to play. Does White need to protect the corner? Click Here To Show Diagram Code `[go]$$Wc White to play $$ \| X X X X . . O O X $$ \| . O O X X X O X X $$ \| . . O X O O X . X $$ \| . O . O O O X . X $$ \| . . . O X X X . . $$ --------------------[/go]` Answer: If White plays elsewhere then Black can kill by ko. Click Here To Show Diagram Code `[go]$$Bc $$ \| X X X X . . O O X $$ \| 3 O O X X X O X X $$ \| 4 . O X O O X . X $$ \| 5 O 2 O O O X . X $$ \| . 1 . O X X X . . $$ --------------------[/go]`

Author:	jlt [ Mon Jun 14, 2021 3:15 pm ]
Post subject:	Re: Tsumegos from real games
Position #23, Black to play. What is the status of the upper left corner? Click Here To Show Diagram Code [go]$$Bc Black to play $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . O . . . O . . . . . . . . . . . . . \| $$ \| . X O O O X X . . . . O X . . . . X . \| $$ \| . X X O O O X X . O O X X X . X . . X \| $$ \| . . X X O O X . . . . O . . . . X X O \| $$ \| . . X O O O O X . X O . O . O . O O O \| $$ \| O O X X X O O X . X O . . . . . . . . \| $$ \| . . O X O O X X . X O . . . . . . . . \| $$ \| O O X X X X O . X . X O . . . . . . . \| $$ \| . . X , O X O . . , X . . O . X . O . \| $$ \| . O O . . O . . . . . . . . X . . . O \| $$ \| . X O . . . O . . . . . O O O O O O X \| $$ \| . X . O . . . . . . . . . X X X X X X \| $$ \| . . X X O . . . . . . . . . . O O . . \| $$ \| . X . X O . . . . . . . . . . O X . . \| $$ \| . X X O . . . O . X . . . . . , X . . \| $$ \| . X O . O . . O X . . . . X . X . . . \| $$ \| . O O . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Edit: coincidence, it's one of the daily problems on the app Tsumego Pro. Click Here To Show Diagram Code [go]$$Bc Answer $$ --------------------------------------- $$ \| . 3 . 5 . 2 7 . . . . . . . . . . . . \| $$ \| 4 O 9 6 8 O 1 . . . . . . . . . . . . \| $$ \| . X O O O X X . . . . O X . . . . X . \| $$ \| . X X O O O X X . O O X X X . X . . X \| $$ \| . . X X O O X . . . . O . . . . X X O \| $$ \| . . X O O O O X . X O . O . O . O O O \| $$ \| O O X X X O O X . X O . . . . . . . . \| $$ \| . . O X O O X X . X O . . . . . . . . \| $$ \| O O X X X X O . X . X O . . . . . . . \| $$ \| . a X , O X O . . , X . . O . X . O . \| $$ \| . O O . . O . . . . . . . . X . . . O \| $$ \| . X O . . . O . . . . . O O O O O O X \| $$ \| . X . O . . . . . . . . . X X X X X X \| $$ \| . . X X O . . . . . . . . . . O O . . \| $$ \| . X . X O . . . . . . . . . . O X . . \| $$ \| . X X O . . . O . X . . . . . , X . . \| $$ \| . X O . O . . O X . . . . X . X . . . \| $$ \| . O O . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] White takes the ko first but Black has a ko threat at "a", so both groups survive.

Author:	jlt [ Mon Sep 20, 2021 8:18 am ]
Post subject:	Re: Tsumegos from real games
Position #24, White to play. Click Here To Show Diagram Code [go]$$Wc White to play $$ --------------------------------------- $$ \| . . X O O . . . . . . . . . . . . . . \| $$ \| . . X X O . . . X X . . . . . X X O . \| $$ \| . . . X O . O . . O X X X X X X O X . \| $$ \| . . X , O . . O O , O O O O O O O O . \| $$ \| . . . . X O X . . . . . . . . . O . . \| $$ \| . . X . X O X X . . . . . . . . X X . \| $$ \| . . . . X O O . . . X O O . . . . . . \| $$ \| . O O O X . . O . X O O X X . X . X . \| $$ \| . X X O X . . . . . . . . . . . X O . \| $$ \| . X . X O O O O O , O O . X X X O . O \| $$ \| . X . X O . X X X X X . O X O O O O . \| $$ \| . X . X O . O O X . . . X O . . . . . \| $$ \| . . X . . . O X . X . . X O . . . . . \| $$ \| . . X X . . X X . . . . X O . . . . . \| $$ \| . . O X . . . . . . . . . . . . . . . \| $$ \| . . O , . . . . . , . . . . O O O O O \| $$ \| . . . O . O . X . . O O O . O X X X O \| $$ \| . . . . . . . . . . . X X X X . . . X \| $$ \| . . . . . . . . . . . . . . . . . X . \| $$ ---------------------------------------[/go] Answer: Click Here To Show Diagram Code [go]$$Wc Answer $$ --------------------------------------- $$ \| . . X O O . . . . . . . . . . . . . . \| $$ \| . . X X O . . . X X . . . . . X X O . \| $$ \| . . . X O . O . . O X X X X X X O X . \| $$ \| . . X , O . . O O , O O O O O O O O . \| $$ \| . . . . X O X . . . . . . . . . O . . \| $$ \| . . X . X O X X . . . . . . . . X X . \| $$ \| . . . . X O O . . . X O O . 1 3 4 . 5 \| $$ \| . O O O X . . O . X O O X X 2 X . X . \| $$ \| . X X O X . . . . . . . . . . . X O . \| $$ \| . X . X O O O O O , O O . X X X O . O \| $$ \| . X . X O . X X X X X . O X O O O O . \| $$ \| . X . X O . O O X . . . X O . . . . . \| $$ \| . . X . . . O X . X . . X O . . . . . \| $$ \| . . X X . . X X . . . . X O . . . . . \| $$ \| . . O X . . . . . . . . . . . . . . . \| $$ \| . . O , . . . . . , . . . . O O O O O \| $$ \| . . . O . O . X . . O O O . O X X X O \| $$ \| . . . . . . . . . . . X X X X . . . X \| $$ \| . . . . . . . . . . . . . . . . . X . \| $$ ---------------------------------------[/go]

Author:	jlt [ Tue Sep 21, 2021 2:14 am ]
Post subject:	Re: Tsumegos from real games
Position #25, White to live. Click Here To Show Diagram Code [go]$$Wc $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . O . . . . . . . . . . . . X . . \| $$ \| . . X O . . . . O . X . . X . X . X . \| $$ \| . . X O . O O . . , . . . . X O X X . \| $$ \| . . . O . X X O O X . . . . . O O O . \| $$ \| . X . . X . . X X O . . . . . . . . . \| $$ \| . . . X . . . X O O . . . . . . . . . \| $$ \| . . . . . X X O X . . X O O O O . . . \| $$ \| . . . X . . O O . . O O X X X X X . . \| $$ \| . O O O O . O . O , O X . . . , . . . \| $$ \| . X . . . . . . . O X X . . . . O X . \| $$ \| . . X . X . X . X . O X . . . O X X . \| $$ \| . . . . . . . . . . O X . . . O X . . \| $$ \| . X . O . X X X O . O X . . . . O O . \| $$ \| . X O . O . . O . . . . . . . . O X . \| $$ \| . O . , . . O . . , . . . . . O . X O \| $$ \| . . . O . . . . O . X . . X X X O O . \| $$ \| . . . . . . . . . . . . . . . . X X . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go]

Author:	kvasir [ Tue Sep 21, 2021 3:32 am ]
Post subject:	Re: Tsumegos from real games
Position #25, White to live. Click Here To Show Diagram Code [go]$$Wc $$ --------------------------------------- $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . O . . . . . . . . . . . . X . . \| $$ \| . . X O . . . . O . X . . X . X . X . \| $$ \| . . X O . O O . . , . . . . X O X X . \| $$ \| . . . O . X X O O X . . . . . O O O . \| $$ \| . X . . X . . X X O . . . . . . . . . \| $$ \| . . . X . . . X O O . . . . . . . . . \| $$ \| . . . . . X X O X . . X O O O O . . . \| $$ \| . . . X . . O O . . O O X X X X X . . \| $$ \| . O O O O . O . O , O X . . . , . . . \| $$ \| . X . . . . . . . O X X . . . . O X . \| $$ \| . . X . X . X . X . O X . 9 . O X X . \| $$ \| . . . . . . . . . . O X . . 4 O X . . \| $$ \| . X . O . X X X O . O X . 3 2 5 O O . \| $$ \| . X O . O . . O . . . 8 7 . 1 . O X . \| $$ \| . O . , . . O . . , . . . . 6 O . X O \| $$ \| . . . O . . . . O . X . . X X X O O . \| $$ \| . . . . . . . . . . . . . . . . X X . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Hope this is correct It was hard to see that allows the net at so I looked at a few moves before coming back to