Life In 19x19 :: Semedori from my game last night

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Semedori from my game last night http://www.lifein19x19.com/viewtopic.php?f=15&t=4481	Page 1 of 1

Author:	yoyoma [ Wed Aug 17, 2011 1:01 pm ]
Post subject:	Semedori from my game last night
Click Here To Show Diagram Code [go]$$c Black to play $$ --------------------------------------- $$ \| . . . . . . . X O X b X X O O . X O X \| $$ \| . . . . . . . X O . X O X O O X X O X \| $$ \| . . . . . . . X O O O O X X X X O O X \| $$ \| . . . , . . . X , . . O O O O O O X X \| $$ \| . . . . . . . . X X . . a X X X X X . \| $$ \| . . . . . . . . . X X X X X . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Here is a simplified version of a position that happened in my game at the Austin club last night. Black to play, what's the status? Should Black play a, b, or tenuki? Or does it not matter?

Author:	Chew Terr [ Wed Aug 17, 2011 1:16 pm ]
Post subject:	Re: Semedori from my game last night
By my counting, it's just dead outright. So tenuki or resign, depending on the board.

Author:	daniel_the_smith [ Wed Aug 17, 2011 1:19 pm ]
Post subject:	Re: Semedori from my game last night
Nice position. Of course the first thing to notice is that black is dead no matter what! It seems to me that if black plays 'b', he then gets to play 4 dame with sente (while white plays inside his own territory), so I guess 'b' is worth 4 points (+1 because of L15, so 5, I guess). If he starts at 'a', only two dame are sente. Of course tenuki would be correct as long as there are plays larger than four points. 'b' and following is all sente for black, so in theory white won't have time to play reverse sente-- black should play this as late as possible because these moves are also great ko threats. Edit: Also, You gave it away by including the word semidori in the title!

Author:	Magicwand [ Wed Aug 17, 2011 1:28 pm ]
Post subject:	Re: Semedori from my game last night
i will not hide..what is the point? "b" is an endgame (i think 3 point value gote). "a" ia a dame. 0 point value. so if you have anything bigger than 3 point gote you should tenuki.

Author:	Bill Spight [ Wed Aug 17, 2011 1:56 pm ]
Post subject:	Re: Semedori from my game last night
Click Here To Show Diagram Code [go]$$c Black has a 3 pt. sente $$ --------------------------------------- $$ \| . . . . . . . X O X . X X O O 1 X O X \| $$ \| . . . . . . . X O . X O X O O X X O X \| $$ \| . . . . . . . X O O O O X X X X O O X \| $$ \| . . . , . . . X , . . O O O O O O X X \| $$ \| . . . . . . . . X X . . . X X X X X . \| $$ \| . . . . . . . . . X X X X X . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] = nakade Now Black has a 1 pt. sente.

Author:	flOvermind [ Thu Aug 18, 2011 2:23 am ]
Post subject:	Re: Semedori from my game last night
Magicwand wrote: i will not hide..what is the point? "b" is an endgame (i think 3 point value gote). "a" ia a dame. 0 point value. so if you have anything bigger than 3 point gote you should tenuki. Are you sure? Black is dead. If black "b", white atari, black capture, and then it's 5 liberties to 5 liberties, with white to move. Bill Spight wrote: Now Black has a 1 pt. sente. Nice one, I missed that

Author:	Magicwand [ Thu Aug 18, 2011 7:02 am ]
Post subject:	Re: Semedori from my game last night
flOvermind wrote: Are you sure? after some more thinking... i think it is two point sente. yes it is dead but if you connect at "b" white have to play two more stones then when when white atari and all sequences are sente. i think bill is wrong on this..

Author:	flOvermind [ Thu Aug 18, 2011 8:06 am ]
Post subject:	Re: Semedori from my game last night
Magicwand wrote: yes it is dead but if you connect at "b" white have to play two more stones then when when white atari and all sequences are sente. i think bill is wrong on this.. Ah, yes, I miscounted the played stones. I always mix these up... So yes, two point sente, plus a one point sente followup. Actually, I think your move and Bill's don't make a difference...

Author:	Bill Spight [ Thu Aug 18, 2011 9:21 am ]
Post subject:	Re: Semedori from my game last night
Click Here To Show Diagram Code [go]$$Wc White reverse sente $$ --------------------------------------- $$ \| . . . . . . . X O X . X X O O . X O X \| $$ \| . . . . . . . X O 1 X O X O O X X O X \| $$ \| . . . . . . . X O O O O X X X X O O X \| $$ \| . . . , . . . X , . . O O O O O O X X \| $$ \| . . . . . . . . X X a . . X X X X X . \| $$ \| . . . . . . . . . X X X X X . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] Result: -25 If Black plays sente, the result is -22. (Black gets 1 point at "a".)

Author:	yoyoma [ Thu Aug 18, 2011 9:54 am ]
Post subject:	Re: Semedori from my game last night
Click Here To Show Diagram Code [go]$$Bc $$ --------------------------------------- $$ \| . . . . . . . X O X . X X O O b X O X \| $$ \| . . . . . . . X O 2 X O X O O X X O X \| $$ \| . . . . . . . X O O O O X X X X O O X \| $$ \| . . . , . . . X , . . O O O O O O X X \| $$ \| . . . . . . . . X X . . 1 X X X X X . \| $$ \| . . . . . . . . . X X X X X . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ ---------------------------------------[/go] In the game I was Black, and I played . After my hand was moving towards b when I suddenly realized white will not respond to my capture by throwing back in but instead by living independently. My beautiful semedori was ruined! Another interesting thing is earlier white had a choice between O18 and Q19, and that choice actually makes a difference.

Author:	Magicwand [ Thu Aug 18, 2011 3:43 pm ]
Post subject:	Re: Semedori from my game last night
Bill Spight wrote: If Black plays sente, the result is -22. (Black gets 1 point at "a".) yes.. then it is 5 point sente? if not ..where did i count wrong?

Author:	Bill Spight [ Thu Aug 18, 2011 4:03 pm ]
Post subject:	Re: Semedori from my game last night
Magicwand wrote: Bill Spight wrote: If Black plays sente, the result is -22. (Black gets 1 point at "a".) yes.. then it is 5 point sente? if not ..where did i count wrong? It's a 3 point sente. I think that you counted the 2 points but not the point at "a". Yes?

Author:	Magicwand [ Thu Aug 18, 2011 7:22 pm ]
Post subject:	Re: Semedori from my game last night
Bill Spight wrote: Magicwand wrote: Bill Spight wrote: If Black plays sente, the result is -22. (Black gets 1 point at "a".) yes.. then it is 5 point sente? if not ..where did i count wrong? It's a 3 point sente. I think that you counted the 2 points but not the point at "a". Yes? yes you are correct... i dont know where i cameup with 5 points (i guess i was really tired when i posted that thread)

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