Life In 19x19 :: tsumego #26

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tsumego #26 http://www.lifein19x19.com/viewtopic.php?f=15&t=7318	Page 1 of 1

Author:	cyclops [ Thu Nov 29, 2012 6:17 pm ]
Post subject:	tsumego #26
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]`

Author:

cyclops [ Thu Nov 29, 2012 6:39 pm ]

Post subject:

Re: tsumego #26

#26a; No, I didn't cheat

Attachments:

26a.sgf [370 Bytes]
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Author:	logan [ Thu Nov 29, 2012 8:15 pm ]
Post subject:	Re: tsumego #26
#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]$$Bc Failure, @ $$-------------- $$\|a.21OO3...... $$\|.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]`

Author:	cyclops [ Fri Nov 30, 2012 7:08 am ]
Post subject:	Re: tsumego #26
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.

Author:	jts [ Fri Nov 30, 2012 10:52 am ]
Post subject:	Re: tsumego #26
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.

Author:	logan [ Fri Nov 30, 2012 4:23 pm ]
Post subject:	Re: tsumego #26
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]$$Bc @ $$-------------- $$\|21.4OO5...... $$\|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.

Author:	cyclops [ Fri Nov 30, 2012 6:01 pm ]
Post subject:	Re: tsumego #26
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.

Author:	jts [ Fri Nov 30, 2012 6:12 pm ]
Post subject:	Re: tsumego #26
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.

Author:	logan [ Fri Nov 30, 2012 6:58 pm ]
Post subject:	Re: tsumego #26
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.

Author:	jts [ Fri Nov 30, 2012 7:59 pm ]
Post subject:	Re: tsumego #26
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.

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