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 Post subject: Dieter's ABC of mistakes - 9
Post #1 Posted: Mon Apr 12, 2021 12:42 am 
Gosei
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Click Here To Show Diagram Code
[go]$$Bc Mistake 9
$$ ---------------------------------------
$$ | . X . X . . . . . . . . X . . . . O . |
$$ | X . X O X . . . . O O O X O O O O X O |
$$ | . X O O X . O . O X . X X X O X O X X |
$$ | . . O X . X O X O X X . . O X X O O X |
$$ | . . O X . X O O X O . . X O . . O X 2 |
$$ | . . O O X . X X X O X . 1 X X X O X . |
$$ | . X O . . X . . . O O O 3 O . O X . . |
$$ | . O O X X O . . O . . . a O . O X . . |
$$ | . . O X O O O . O X X . X X . O . . . |
$$ | . . X O X O . O X , . . . . . , b X . |
$$ | . . X O . X . O X . . . . X . O . c . |
$$ | . . X O . . . O X . . . . . . . . . . |
$$ | . O . O X . O . . . . X . X X O O X . |
$$ | . . O . O O . X . . . . O O O X X X . |
$$ | . O X X . . X . X X X . . . . O O X . |
$$ | . . O , X X . O X O X X O O . O X . . |
$$ | . . . O O X . O X O X O O X O O X . . |
$$ | . . . . . . . O O O O . O X O X X . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ ---------------------------------------[/go]


White has ended the [ko] in the upper right and Black follows up the threat at B1 with cutting at B3. White's next move is not game losing but there was no need to spoil 35 points of a 60 point lead. Where should White play, ''a'', ''b'' or ''c''?


Last edited by Uberdude on Mon Apr 12, 2021 11:48 pm, edited 1 time in total.
Added coordinates

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 Post subject: Re: Dieter's ABC of mistakes - 9
Post #2 Posted: Mon Apr 12, 2021 8:15 am 
Gosei
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The biggest group is Black's top group, which only has one eye, I don't see any reason not to play "a" unless White doesn't have enough liberties.

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



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



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


How to count liberties now? White seems to have more but I am not sure.

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 Post subject: Re: Dieter's ABC of mistakes - 9
Post #3 Posted: Mon Apr 12, 2021 11:48 pm 
Judan

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Just from the 35 point clue, the answer is a, and you played b. C would lose even more.

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 Post subject: Re: Dieter's ABC of mistakes - 9
Post #4 Posted: Tue Apr 13, 2021 8:19 am 
Gosei
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Solution

My mistake was to play C. Now the difference between A and B is subtle. The instinctive move A leads to a fight where extra weight and loss of liberties affects the outcome of a multi-step ko, Black being komaster:

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


Click Here To Show Diagram Code
[go]$$Wc Mistake 9
$$ ---------------------------------------
$$ | . X . X . . . . . . . . X . . . . O . |
$$ | X . X O X . . . . O O O X O O O O . O |
$$ | . X O O X . O . O X . X X X O X O . . |
$$ | . . O X . X O X O X X . . O X X O O 3 |
$$ | . . O X . X O O X O . . X O . . O B O |
$$ | . . O O X . X X X O X . X X X X O # 5 |
$$ | . X O . . X . . . O O O X O . O X 7 X |
$$ | . O O X X O . . O . . X O O . O X 2 1 |
$$ | . . O X O O O . O X X . X X . O . X 4 |
$$ | . . X O X O . O X , . . . . . , O X X |
$$ | . . X O . X . O X . . . . X . O a O X |
$$ | . . X O . . . O X . . . . . . 6 0 O O |
$$ | . O . O X . O . . . . X . X X O O X . |
$$ | . . O . O O . X . . . . O O O X X X . |
$$ | . O X X . . X . X X X . . . . O O X . |
$$ | . . O , X X . O X O X X O O . O X . . |
$$ | . . . O O X . O X O X O O X O O X . . |
$$ | . . . . . . . O O O O . O X O X X . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ ---------------------------------------[/go]


:b8: at the squared stone, :w9: at the circled. Next is A.

Without the exchange in the first diagram, White can win the ko and allow Black an easy way out with the top group. With the exchange, Black has more damaging forcing moves. Or so it seems - I haven't checked the full gamut of variations here.

Obviously I didn't intend to have this superhuman analysis to be part of the exercise.

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