tsumego #26

For lessons, as well as threads about specific moves, and anything else worth studying.
Post Reply
User avatar
cyclops
Lives in sente
Posts: 801
Joined: Mon May 10, 2010 3:38 pm
Rank: KGS 7 kyu forever
GD Posts: 460
Location: Amsterdam (NL)
Has thanked: 353 times
Been thanked: 107 times
Contact:

tsumego #26

Post by cyclops »

Day #26 November 30th
5 years ago we had a 10 post discussion about the #26 series.
#26a Advanced problem
Click Here To Show Diagram Code
[go]$$Bc
$$--------------
$$|....OO.......
$$|.OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|X.OX.XO.O....
$$|..OX.XO......
$$|..O..........
$$|.............[/go]
#26b Intermediate problem
Click Here To Show Diagram Code
[go]$$Bc
$$----------
$$|....OX...
$$|XX.XXO.O.
$$|OX.XOO...
$$|.OXO.....
$$|.O.O.....
$$|.........
$$|.O.......
$$|.........[/go]
#26c Elementary problem
Click Here To Show Diagram Code
[go]$$Bc
$$----------
$$|.XX.O....
$$|.OOOOX.X.
$$|OOXXXX...
$$|.XX,.....
$$|.........
$$|.X.......
$$|.........[/go]
User avatar
cyclops
Lives in sente
Posts: 801
Joined: Mon May 10, 2010 3:38 pm
Rank: KGS 7 kyu forever
GD Posts: 460
Location: Amsterdam (NL)
Has thanked: 353 times
Been thanked: 107 times
Contact:

Re: tsumego #26

Post by cyclops »

#26a; No, I didn't cheat ;)
Attachments
26a.sgf
(370 Bytes) Downloaded 529 times
logan
Lives in gote
Posts: 641
Joined: Sat May 29, 2010 11:52 am
GD Posts: 9
Has thanked: 141 times
Been thanked: 437 times

Re: tsumego #26

Post by logan »

#26a Advanced problem
Click Here To Show Diagram Code
[go]$$Bc
$$--------------
$$|21..OO.......
$$|3OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|X.OX.XO.O....
$$|..OX.XO......
$$|..O..........
$$|.............[/go]
Click Here To Show Diagram Code
[go]$$Bc Failure, :w4: @ :b1:
$$--------------
$$|a.21OO3......
$$|.OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|XbOX.XO.O....
$$|..OX.XO......
$$|..O..........
$$|.............[/go]
#26b Intermediate problem
Click Here To Show Diagram Code
[go]$$Bc
$$----------
$$|.324OX...
$$|XX5XXO.O.
$$|OX1XOO...
$$|.OXO.....
$$|.O.O.....
$$|.........
$$|.O.......
$$|.........[/go]
#26c Elementary problem
Click Here To Show Diagram Code
[go]$$Bc
$$----------
$$|1XX.O....
$$|.OOOOX.X.
$$|OOXXXX...
$$|.XX,.....
$$|.........
$$|.X.......
$$|.........[/go]
User avatar
cyclops
Lives in sente
Posts: 801
Joined: Mon May 10, 2010 3:38 pm
Rank: KGS 7 kyu forever
GD Posts: 460
Location: Amsterdam (NL)
Has thanked: 353 times
Been thanked: 107 times
Contact:

Re: tsumego #26

Post by cyclops »

I am not sure we agree on the advanced problem.
IMO, my two first variants are b's best play resulting in a ko to connect and live.
User avatar
jts
Oza
Posts: 2665
Joined: Sat Sep 18, 2010 4:17 pm
Rank: kgs 6k
GD Posts: 0
Has thanked: 310 times
Been thanked: 634 times

Re: tsumego #26

Post by jts »

cyclops,
Are you sure? I read logan's solution as ensuring that B either gets a ko for the whole group, or captures the tail in sente.
logan
Lives in gote
Posts: 641
Joined: Sat May 29, 2010 11:52 am
GD Posts: 9
Has thanked: 141 times
Been thanked: 437 times

Re: tsumego #26

Post by logan »

Thank-you for the support jts, however I made a mistake. Simple reason:
My solution White begin ko (Black find first threat)
Click Here To Show Diagram Code
[go]$$Bc :w6: @ :w2:
$$--------------
$$|21.4OO5......
$$|3OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|X.OX.XO.O....
$$|..OX.XO......
$$|..O..........
$$|.............[/go]
Correct solution Black begin ko (White find first threat).
Click Here To Show Diagram Code
[go]$$Bc
$$--------------
$$|21.4OO3......
$$|5OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|X.OX.XO.O....
$$|..OX.XO......
$$|..O..........
$$|.............[/go]
It's minor, but important difference. In game with strong players one ko threat can be difference between win or lose entire ko.
User avatar
cyclops
Lives in sente
Posts: 801
Joined: Mon May 10, 2010 3:38 pm
Rank: KGS 7 kyu forever
GD Posts: 460
Location: Amsterdam (NL)
Has thanked: 353 times
Been thanked: 107 times
Contact:

Re: tsumego #26

Post by cyclops »

thx for your support logan. Your solution is my first variant. So now we have 6 posts on these problems. Not too bad compared to the 10 posts 5 years ago.
User avatar
jts
Oza
Posts: 2665
Joined: Sat Sep 18, 2010 4:17 pm
Rank: kgs 6k
GD Posts: 0
Has thanked: 310 times
Been thanked: 634 times

Re: tsumego #26

Post by jts »

You recanted too quickly, logan!
The threat is important, but W's option to sac the tail is, imho opinion, way more important than a ko threat here or there. (Obviously this problem, like any problem with an option to ko or compromise, is very dependent on threats.)
Click Here To Show Diagram Code
[go]$$Bc
$$--------------
$$|21.5OO.......
$$|3OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|X4OX.XO.O....
$$|6.OX.XO......
$$|..O..........
$$|.............[/go]
Sente for B!
Click Here To Show Diagram Code
[go]$$Bc
$$--------------
$$|214.OO3......
$$|.OOOXOX.X..O.
$$|OOXXXOX.X.O..
$$|OXX,.XO..O...
$$|X.OX.XO.O....
$$|..OX.XO......
$$|..O..........
$$|.............[/go]
In Cyclops' line, B has an extra threat if W wants to ko... and gote if he doesn't.
logan
Lives in gote
Posts: 641
Joined: Sat May 29, 2010 11:52 am
GD Posts: 9
Has thanked: 141 times
Been thanked: 437 times

Re: tsumego #26

Post by logan »

In these problems you should always look for the strongest resistance. It will be solution 99% of the time. (Exceptions can be when author says otherwise & whole board problems.) Since the rest of the board is invisible then you can consider other factors as ceteris paribus and ignore them. So in this instance, White's strongest resistance is ko.
User avatar
jts
Oza
Posts: 2665
Joined: Sat Sep 18, 2010 4:17 pm
Rank: kgs 6k
GD Posts: 0
Has thanked: 310 times
Been thanked: 634 times

Re: tsumego #26

Post by jts »

I think the convention is that you look for the most stubborn resistance to make sure that you can refute all lines (and often the most stubborn resistance has the most interesting suji), but you certainly don't play out an inferior line because it gives you a better position in the most stubborn resistance. Connecting in sente, rather than in gote, is worth gobs and gobs of points.
Post Reply