Life In 19x19

Posted: **Fri May 22, 2020 11:28 am**

Click Here To Show Diagram Code: [go]$$W White to play $$ --------------------------------------- $$ | . . . . . . . . 4 2 3 X . X X . X . . | $$ | . . . X . . . . X O O O X X X X O O . | $$ | . . O . . X . . X X B O X O O X O . . | $$ | . . . O . . . . . , X O X O X X O . . | $$ | . . . . . . . . . . X O O O O X X O . | $$ | . . O . . . . . . . B O X X 6 O X O . | $$ | . . . . . . . . . . X O 7 O O O X O . | $$ | . . . . . . . . . . X O O O X X X O . | $$ | . . . . . . . . . . X O X X X X O O . | $$ | . . . X . . . . O O X O X O W X O O X | $$ | . . . X O . . . O X . X O . O X O X . | $$ | . . X O . O O O X X . . . . W X X X 1 | $$ | . . X O . X X O X O . O O O O O O O 5 | $$ | . . X O . . . X X O . . X X X X O . . | $$ | . X O O O X . X . O X . . X . X O . . | $$ | . X O , O X . . . O . . O X X O . . . | $$ | . . X O O O X X X O . X O X O O . . . | $$ | . X . X . O X . X O X . X . X O . . . | $$ | . . X . . . . . X O . . . X O O . . . | $$ ---------------------------------------[/go]

The marked stones are outside liberties, incidental to the problem/

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

White takes first

Click Here To Show Diagram Code: [go]$$W White to play $$ --------------------------------------- $$ | . . . . . . . . 4 1 8 X 6 X X 9 X 7 . | $$ | . . . X . . . . X O O O X X X X O O . | $$ | . . O . . X . . X X B O X O O X O . . | $$ | . . . O . . . . . , X O X O X X O . . | $$ | . . . . . . . . . . X O O O O X X O . | $$ | . . O . . . . . . . B O X X . O X O . | $$ | . . . . . . . . . . X O . O O O X O . | $$ | . . . . . . . . . . X O O O X X X O . | $$ | . . . . . . . . . . X O X X X X O O 5 | $$ | . . . X . . . . O O X O X O W X O O X | $$ | . . . X O . . . O X . X O . O X O X . | $$ | . . X O . O O O X X . . . . W X X X 2 | $$ | . . X O . X X O X O . O O O O O O O 3 | $$ | . . X O . . . X X O . . X X X X O . . | $$ | . X O O O X . X . O X . . X . X O . . | $$ | . X O , O X . . . O . . O X X O . . . | $$ | . . X O O O X X X O . X O X O O . . . | $$ | . X . X . O X . X O X . X . X O . . . | $$ | . . X . . . . . X O . . . X O O . . . | $$ ---------------------------------------[/go]

White will always take a ko to prevent Black from connecting.

Edited diagram 2, voiding jlt's next comment

Posted: **Fri May 22, 2020 1:26 pm**

Knotwilg, you mistyped what you had in mind in diagram 2 since there are two

on the board and

on an intersection that is already occupied by a white stone.

Anyway I think that

starting from your diagram 1 leads to a ko (this is what happened in my game), while

in your diagram 3 is the correct move, White wins the semeai without needing to fight a ko.

Posted: **Tue May 26, 2020 11:42 am**

Problem #8: Black to play. Can Black save the marked stone?

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

Posted: **Wed Jun 17, 2020 12:38 am**

Possible variation:

Posted: **Wed Jun 17, 2020 12:48 am**

Problem #9. I was Black in this game. Between moves 50 and 130 I thought that I had killed the upper left corner. Probably White thought the same as well, as he didn't try to live. When he finally made an attempt at move 130, he didn't make the correct choice.

White to play and save the marked stones.

Click Here To Show Diagram Code: [go]$$Wc White to play and save the marked stones $$ --------------------------------------- $$ | . . . . . . . . X . . . . . . . X O . | $$ | . . . . . . X X . X O . . . O X . O . | $$ | . . . . X . O X X O O . O O O X X X . | $$ | . . W W X . . O O , . . . X X X O X . | $$ | . . . . . . O . X O . . X . X O O O . | $$ | . . X X . X X O . . . . X X X X O . . | $$ | . . . . . . . O . . . . X O O O . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . X X O . . . X . O O X . . | $$ | . . X X X . . O . , . O . X O X X . . | $$ | . . X O . O . . . . . . O O X O . . . | $$ | . . X O . O . . . . . . . O X O O X . | $$ | . . O X . . . . . . . . X O X . X . . | $$ | . . O . . . . . . . . O O X . X . . . | $$ | . . . . . . . O X . O O X . . . . . . | $$ | . . . O . . . . O O . X . X . O X . . | $$ | . . . . O . O O X X O O X . . X . . . | $$ | . . . O X X X X O X X . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Posted: **Wed Jun 17, 2020 2:38 am**

Click Here To Show Diagram Code: [go]$$Wc White to play and save the marked stones $$ --------------------------------------- $$ | . . . . . . . . X . . . . . . . X O . | $$ | . 1 . a . . X X . X O . . . O X . O . | $$ | . . . . X . O X X O O . O O O X X X . | $$ | . . W W X . . O O , . . . X X X O X . | $$ | . b . . . . O . X O . . X . X O O O . | $$ | . . X X . X X O . . . . X X X X O . . | $$ | . . . . . . . O . . . . X O O O . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . X X O . . . X . O O X . . | $$ | . . X X X . . O . , . O . X O X X . . | $$ | . . X O . O . . . . . . O O X O . . . | $$ | . . X O . O . . . . . . . O X O O X . | $$ | . . O X . . . . . . . . X O X . X . . | $$ | . . O . . . . . . . . O O X . X . . . | $$ | . . . . . . . O X . O O X . . . . . . | $$ | . . . O . . . . O O . X . X . O X . . | $$ | . . . . O . O O X X O O X . . X . . . | $$ | . . . O X X X X O X X . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Does

make miai of A and B?

Posted: **Wed Jun 17, 2020 2:58 am**

This seems to lead to a ko

Click Here To Show Diagram Code: [go]$$Wc $$ --------------------------------------- $$ | . 8 9 . . . . . X . . . . . . . X O . | $$ | 0 1 . 3 4 . X X . X O . . . O X . O . | $$ | . 6 . 5 X . O X X O O . O O O X X X . | $$ | . 7 W W X . . O O , . . . X X X O X . | $$ | . 2 . . . . O . X O . . X . X O O O . | $$ | . . X X . X X O . . . . X X X X O . . | $$ | . . . . . . . O . . . . X O O O . . . | $$ | . . . . . . . . . . . . . . . . O . . |[/go]

Katago suggests another move

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

It is really necessary for Black to block at :4:, otherwise a variation like this can happen:

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

Posted: **Tue Nov 10, 2020 12:02 pm**

Problem #10, White to play. What is the status of the C10 group?

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

Posted: **Thu Nov 12, 2020 1:37 pm**

Answer:

It's a ko.

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

White has local ko threats: capture A16 or capture F13.

In order to live, White just needs to ignore one ko threat and then can live with B10: after

ko threat,

responds,

takes ko,

ko threat, then White is alive (if Black a then White b).

Click Here To Show Diagram Code: [go]$$Wm11 $$ | X X X . . . . . . . X O . . . X . . . | $$ | O O X . X . . . . . . O O . X O O . . | $$ | a O O . O X . X . X . O X X . O X . . | $$ | 1 X O O O X . . . . X . . . O O . . . | $$ | X X O X O O . O X X . . X X X O O . . | $$ | b 3 O X O . O X X O . . . . . O X . . | $$ | O O X X X . X O O O . . O O O O . X . | $$ | . X X . . X . . X O O O X X X . . . . | $$ | . . . X . X . X . O X X . . . . X . . |[/go]

Move

is interesting because go problems rarely teach us these kinds of moves. In most go problems, only one group is involved and we don't threaten to connect to another group before living locally.

Posted: **Thu Nov 12, 2020 2:20 pm**

Problem #11, White to play.

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

Posted: **Fri Nov 20, 2020 2:19 pm**

Posted: **Wed Dec 09, 2020 7:45 am**

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:

Posted: **Fri Dec 11, 2020 10:48 am**

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:

Posted: **Mon Jan 11, 2021 1:35 am**

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:

Posted: **Sun Jan 17, 2021 9:35 am**

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]

Life In 19x19

Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games

Re: Tsumegos from real games