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 3

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.

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