It is currently Sat Jan 22, 2022 1:32 am

View unanswered posts | View active topics View unread posts | View new posts | View your posts


Board index » Improve Your Game » Study Group

All times are UTC - 8 hours [ DST ]



Post new topic Reply to topic  Page 2 of 4
  [ 77 posts ]  Go to page Previous  1, 2, 3, 4  Next
  Print view Previous topic | Next topic 
Author Message
Offline xela
 Post subject: Re: Tsumegos from real games
Post #21 Posted: Tue Feb 25, 2020 4:12 am 
Lives in gote

Posts: 430
Location: Adelaide, South Australia
Liked others: 173
Was liked: 224
Rank: Australian 2 dan
GD Posts: 200
Tsumego 4, minor detail of move order:
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . b 9 . . . . . . . . . . . . . |
$$ | . . W . 5 4 0 8 . . . . . . . . . . . |
$$ | . X W a 3 O 1 X O . . . . O X . . . . |
$$ | . X X O 6 X O O 2 O . . . O X X X . . |
$$ | . X O O . 7 X X O . . . . . . . O . . |
$$ | . . X X O O . . O O . . . . X X O . . |
$$ | . . . . X O X X . X O . . . . O . . . |
$$ | . . . X X X O X . X . . . . . . . . . |
$$ | . . X . . O O . . . . . . . . . . . . |[/go]

:b11: at a. If black omits :b9:, then white can play b and save the :wc: stones.

This post by xela was liked by: Kirby
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #22 Posted: Tue Feb 25, 2020 6:15 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Re: tsumego 3. Here is Katago's analysis.


Suppose first that White pushes, Black blocks and White cuts.
Click Here To Show Diagram Code
[go]$$Wc The four black stones are captured
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O X X . . . . . . . . . . . . . |
$$ | . . O X . O . X . . . . . X . X X . . |
$$ | . . O X . . . . . , . . . . . O . . . |
$$ | . . O X . . 7 5 6 . . . . . . . O . . |
$$ | . . O O X X 2 3 4 . . . . . . O X . . |
$$ | . . . O O X 1 X X O . . . . . . O . . |
$$ | . . . . X W W W W X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . . , . X . . . , . . . . . , . . . |[/go]


(White shouldn't play :w7: at E15, otherwise Black sacrifices three stones and plays :b8: at :w7:.)

If Black protects the four stones with :b6:, then other stones are caught in a ladder.

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


However, before blocking, Black may want to make the exchange K14-L13 first, in which case the above variations don't work anymore, so White has to play :w5: differently. Black has to extend at :b6: otherwise the preceding variations work again, and then :w7: captures the cutting stone K12 in a ladder.

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


xela wrote:
But I don't think of this as tesuji, white is playing fairly blunt moves.


I know these moves are blunt, but because my reading is too shallow, I couldn't see that a succession of 7 blunt moves actually works. That's one of the reasons why I am a kyu player...
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #23 Posted: Tue Feb 25, 2020 6:30 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Tsumego 4, analysis by Katago:

Suppose White cuts with :w6: as in Kirby's and xela's posts, then White loses somes stones but ends in sente: after :w10:, Black needs to play "a".
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . 9 8 . . . . . . . . . . . . . |
$$ | . . O . 5 4 . 0 . . . . . . . . . . . |
$$ | . X O a 3 O 1 X O . . . . O X . . . . |
$$ | . X X O 6 X O O 2 O . . . O X X X . . |
$$ | . X O O . 7 X X O . . . . . . . O . . |
$$ | . . X X O O . . O O . . . . X X O . . |
$$ | . . . . X O X X . X O . . . . O . . . |
$$ | . . . X X X O X . X . . . . . . . . . |
$$ | . . X . . O O . . . . . . . . . . . . |[/go]


So White won't bother cutting at :w6: and plays as follows:
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . 7 6 . . . . . . . . . . . . . |
$$ | . . O . 5 4 . 8 . . . . . . . . . . . |
$$ | . X O . 3 O 1 X O . . . . O X . . . . |
$$ | . X X O . X O O 2 O . . . O X X X . . |
$$ | . X O O 9 . X X O . . . . . . . O . . |
$$ | . . X X O O . . O O . . . . X X O . . |
$$ | . . . . X O X X . X O . . . . O . . . |
$$ | . . . X X X O X . X . . . . . . . . . |
$$ | . . X . . O O . . . . . . . . . . . . |[/go]
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #24 Posted: Wed Apr 29, 2020 8:48 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Tsumego #5: An easy one but I didn't take the trouble to read it during the game.

White to play. Assume White is alive. What is the status of the black group?

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

This post by jlt was liked by: Bill Spight
Top
 Profile  
 
Offline EricBackus
 Post subject: Re: Tsumegos from real games
Post #25 Posted: Wed Apr 29, 2020 10:03 am 
Dies in gote

Posts: 57
Liked others: 3
Was liked: 26
Rank: 2 kyu
GD Posts: 109
Universal go server handle: EricBackus
jlt wrote:
Tsumego #5: An easy one but I didn't take the trouble to read it during the game.

White to play. Assume White is alive. What is the status of the black group?

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

I think: Black is alive, but white can make a gote seki.

Click Here To Show Diagram Code
[go]$$Wc This attack fails
$$ ----------------
$$ O O X . . 1 2 5 |
$$ O X X X X 4 3 6 |
$$ O O O O O X X X |
$$ . O O . O O O O |[/go]

Click Here To Show Diagram Code
[go]$$Wc Gote seki
$$ ----------------
$$ O O X . 5 2 1 . |
$$ O X X X X 4 . 3 |
$$ O O O O O X X X |
$$ . O O . O O O O |[/go]

Black could alternatively make this a ko, but this is unlikely to be better than seki.
Click Here To Show Diagram Code
[go]$$Wc Ko, white takes first
$$ ----------------
$$ O O X . 3 4 1 . |
$$ O X X X X . 2 . |
$$ O O O O O X X X |
$$ . O O . O O O O |[/go]

This post by EricBackus was liked by: jlt
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #26 Posted: Sat May 09, 2020 3:57 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Tsumego #6: Black to play. Can Black kill a group?

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

This post by jlt was liked by: Bill Spight
Top
 Profile  
 
Offline Harleqin
 Post subject: Re: Tsumegos from real games
Post #27 Posted: Sat May 09, 2020 6:04 am 
Lives in sente
User avatar

Posts: 845
Liked others: 338
Was liked: 141
Rank: German 2 dan
Like this probably:

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . O X . . O O . O X . X X O X O O . . |
$$ | . O X O O O X O O X . . O X . X O . . |
$$ | O X O O X X X X X , . . . X X X . O . |
$$ | . X X X . . . . . . X . O . . . X O O |
$$ | . X . . X . O O O . X O 3 a . . X O X |
$$ | . . X O . O . X O X O 1 . O O X . X . |
$$ | . X O . . . O X O X 2 O O . O O X . X |
$$ | . X O . O . O O X X . X O O X X X X O |
$$ | X O O X O X . . . , . X O X . X . O . |
$$ | . X . O O X . O . . . . X . X X . O . |
$$ | . . . O X X . . . . X X X X O O O . . |
$$ | . X O O . . . X . X X O O O O X . . . |
$$ | . X O X . . . . O X O . . . O X O O . |
$$ | . X O X . X . X X O . . O X . X X X . |
$$ | . X X O . . X . O , O . O X . , . . . |
$$ | . . X O . O X . X O . O X O . X . . . |
$$ | . O O . O . O X X X O O X X . . . . . |
$$ | . . . . . . O . O O . . . . . . . . . |
$$ ---------------------------------------[/go]


If 2 captures, 3 at a.

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

This post by Harleqin was liked by: jlt
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #28 Posted: Sat May 09, 2020 8:33 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
It seems that this is the correct :b1:, but White can play :w2: differently and get a ko.
Top
 Profile  
 
Offline Harleqin
 Post subject: Re: Tsumegos from real games
Post #29 Posted: Sun May 10, 2020 2:54 pm 
Lives in sente
User avatar

Posts: 845
Liked others: 338
Was liked: 141
Rank: German 2 dan
Oh.
Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . O X . . O O . O X . X X O X O O . . |
$$ | . O X O O O X O O X . . O X . X O . . |
$$ | O X O O X X X X X , . . . X X X . O . |
$$ | . X X X . . . . . . X 7 O 2 . . X O O |
$$ | . X . . X . O O O . X O . 4 3 . X O X |
$$ | . . X O . O . X O X O 1 6 O O X . X . |
$$ | . X O . . . O X O X 5 O O . O O X . X |
$$ | . X O . O . O O X X . X O O X X X X O |
$$ | X O O X O X . . . , . X O X . X . O . |
$$ | . X . O O X . O . . . . X . X X . O . |
$$ | . . . O X X . . . . X X X X O O O . . |
$$ | . X O O . . . X . X X O O O O X . . . |
$$ | . X O X . . . . O X O . . . O X O O . |
$$ | . X O X . X . X X O . . O X . X X X . |
$$ | . X X O . . X . O , O . O X . , . . . |
$$ | . . X O . O X . X O . O X O . X . . . |
$$ | . O O . O . O X X X O O X X . . . . . |
$$ | . . . . . . O . O O . . . . . . . . . |
$$ ---------------------------------------[/go]

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

This post by Harleqin was liked by: jlt
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #30 Posted: Fri May 22, 2020 8:29 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
This one should be easy.

Problem #7: White to play and win the capturing race.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . X . X X . X . . |
$$ | . . . X . . . . X O O O X X X X O O . |
$$ | . . O . . X . . X X . O X O O X O . . |
$$ | . . . O . . . . . , X O X O X X O . . |
$$ | . . . . . . . . . . X O O O O X X O . |
$$ | . . O . . . . . . . . O X X . O X O . |
$$ | . . . . . . . . . . X O . O O O X O . |
$$ | . . . . . . . . . . X O O O X X X O . |
$$ | . . . . . . . . . . X O X X X X O O . |
$$ | . . . X . . . . O O X O X O . X O O X |
$$ | . . . X O . . . O X . X O . O X O X . |
$$ | . . X O . O O O X X . . . . . X X X . |
$$ | . . X O . X X O X O . O O O O O O O . |
$$ | . . 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]
Top
 Profile  
 
Offline Knotwilg
 Post subject: Re: Tsumegos from real games
Post #31 Posted: Fri May 22, 2020 11:28 am 
Gosei
User avatar

Posts: 2012
Location: Ghent, Belgium
Liked others: 306
Was liked: 889
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
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


Last edited by Knotwilg on Fri May 22, 2020 1:29 pm, edited 3 times in total.
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #32 Posted: Fri May 22, 2020 1:26 pm 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Knotwilg, you mistyped what you had in mind in diagram 2 since there are two :w2: on the board and :b7: on an intersection that is already occupied by a white stone.

Anyway I think that :w1: starting from your diagram 1 leads to a ko (this is what happened in my game), while :w1: in your diagram 3 is the correct move, White wins the semeai without needing to fight a ko.

This post by jlt was liked by: Knotwilg
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #33 Posted: Tue May 26, 2020 11:42 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
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]
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #34 Posted: Wed Jun 17, 2020 12:38 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Possible variation:

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 7 3 . . . . . . . . . . . . . . . . |
$$ | . 4 . . 5 O . . . . . . . O O X . . . |
$$ | . O 1 B O 6 . . . , . . O X O X . . . |
$$ | O 2 O O X O . . . . . O . X O X . . . |
$$ | . O X X X . . . . . . . X . X X O . . |
$$ | . X X . X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #35 Posted: Wed Jun 17, 2020 12:48 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
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]
Top
 Profile  
 
Offline Knotwilg
 Post subject: Re: Tsumegos from real games
Post #36 Posted: Wed Jun 17, 2020 2:38 am 
Gosei
User avatar

Posts: 2012
Location: Ghent, Belgium
Liked others: 306
Was liked: 889
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
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 :w1: make miai of A and B?
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #37 Posted: Wed Jun 17, 2020 2:58 am 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
Not sure.

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


and then?


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]
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #38 Posted: Tue Nov 10, 2020 12:02 pm 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
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]

This post by jlt was liked by: marvin
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #39 Posted: Thu Nov 12, 2020 1:37 pm 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
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 :w9: ko threat, :b10: responds, :w11: takes ko, :b12: 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 :w1: 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.
Top
 Profile  
 
Offline jlt
 Post subject: Re: Tsumegos from real games
Post #40 Posted: Thu Nov 12, 2020 2:20 pm 
Gosei
User avatar

Posts: 1464
Liked others: 127
Was liked: 419
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]
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  Page 2 of 4
  [ 77 posts ]  Go to page Previous  1, 2, 3, 4  Next

Board index » Improve Your Game » Study Group

All times are UTC - 8 hours [ DST ]

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group