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SDK Life & Death from a tournament game

https://www.lifein19x19.com/viewtopic.php?t=4857

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SDK Life & Death from a tournament game

Posted: Tue Oct 18, 2011 8:29 pm
by Chew Terr
Click Here To Show Diagram Code
[go]$$Wcm97 Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | . X X . X . . . . . . . . . . . O . . |
$$ | . O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | . O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X . . . X . . . . . . . . . . . . . |
$$ | . X . 1 . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I went to a tournament last weekend and saw a life and death problem in a fairly pure form in a real game, so I thought I'd share. It helped that I'd only recently done two books that had similar problems.

Black to play and live. I'll post the rest of the game with the solution I used later (maybe multiple work?)

Re: SDK Life & Death from a tournament game

Posted: Tue Oct 18, 2011 8:55 pm
by jts
d2, then c1 and e1 are miai. When W connects at a3 or descends at g2, put the white stones in atari. ?

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 12:17 am
by gogameguru
Interesting game, was 97 a ko threat?

Maybe 97 one line higher is more interesting for white? ;) There really is a lot of aji here, and also a capturing race, but I'll leave it for others to do some reading too.

Click Here To Show Diagram Code
[go]$$Wcm97 Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | . X X . X . . . . . . . . . . . O . . |
$$ | . O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | . O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X . 1 . X . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I'm looking forward to seeing how the game went :).

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 8:07 am
by Chew Terr
Guru:
Click Here To Show Diagram Code
[go]$$Wcm97 Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | . X X . X . . . . . . . . . . . O . . |
$$ | . O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | . O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X 6 1 . X 2 3 . . . . . . . . . . . |
$$ | . X . 4 5 . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Actually, this is very similar to a go problem I did just yeserday. However, even after reading the solution diagram, I had a hard time figuring out that the solution was ko. This is essentially the same solution, though in this case, I THINK my eyespace may be big enough to do a victory race with the bottom-left white group? Is this solution correct?


And the full game in question (Obviously I'm black):


This game wasn't an amazing performance, but it was sure fun to play, and it was cool that it condensed into such a clear-cut tsumego.

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 8:21 am
by topazg
@Chew

I was thinking this is better?

Click Here To Show Diagram Code
[go]$$Wcm97 Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | . X X . X . . . . . . . . . . . O . . |
$$ | . O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | . O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X 6 1 8 X 2 3 . . . . . . . . . . . |
$$ | . X 7 4 5 0 . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Wcm107 Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | 4 X X . X . . . . . . . . . . . O . . |
$$ | 8 O X O X O . . . . . . . . . . . . . |
$$ | 3 O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | 2 O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X X . X X X O . . . . . . . . . . . |
$$ | 6 X . 1 . X 7 5 . . . . . . . . . . . |
$$ ---------------------------------------[/go]


or:


Click Here To Show Diagram Code
[go]$$Wcm107 Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | 4 X X . X . . . . . . . . . . . O . . |
$$ | 3 O X O X O . . . . . . . . . . . . . |
$$ | 8 O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | 2 O O X O X . X . , . . . . . X . . . |
$$ | 5 O X X X O O O . . O . X . . . . . . |
$$ | O X X . X X X O . . . . . . . . . . . |
$$ | 6 X . 1 . X . 7 . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The ko is an unnecessary risk, no?

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 8:23 am
by Chew Terr
Topazg:
Sorry, that's exactly what I meant by '...though in this case, I THINK my eyespace may be big enough to do a victory race with the bottom-left white group?'

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 8:27 am
by topazg
Ah, apologies :)

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 8:27 am
by Chew Terr
topazg wrote:Ah, apologies :)


Not at all, it was me who was unclear. =)

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 3:50 pm
by Solomon
Hmm...I'm a little surprised White resigned there. Seems a bit premature imo.

Re: SDK Life & Death from a tournament game

Posted: Wed Oct 19, 2011 5:18 pm
by gogameguru
Araban wrote:Hmm...I'm a little surprised White resigned there. Seems a bit premature imo.

Yeah, but I guess white is not as strong as you Araban. Apparently they felt it was hopeless...

Chew Terr wrote:Guru:
Click Here To Show Diagram Code
[go]$$Wc Black to live
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | . X X . X . . . . . . . . . . . O . . |
$$ | . O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | . O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X 6 1 . X 2 3 . . . . . . . . . . . |
$$ | . X . 4 5 . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Actually, this is very similar to a go problem I did just yeserday. However, even after reading the solution diagram, I had a hard time figuring out that the solution was ko. This is essentially the same solution, though in this case, I THINK my eyespace may be big enough to do a victory race with the bottom-left white group? Is this solution correct?

@Chew yeah that's more or less it :). By the way, please just call me David everyone (Go Game Guru is the name of our site, but seriously, I don't go around calling myself that... It's kind of awkward now that I made this account early on and then started using my own picture instead of our logo. I don't believe I can change it now. :oops: ).

And here's another interesting idea to consider...

Click Here To Show Diagram Code
[go]$$Wc :w7: at :b2: - exchanging 'a' for 'b' is aji keshi and also loses liberties.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | . X X . X . . . . . . . . . . . O . . |
$$ | . O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . . . . . . . . . . . . . |
$$ | X . O O O X . X . . O . . . . . . . . |
$$ | . O O X O X . X . , . . . . . X . . . |
$$ | . O X X X O O O . . O . X . . . . . . |
$$ | O X 4 1 6 X a b . . . . . . . . . . . |
$$ | . X 5 2 3 8 . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


After :b8: is on the board black has a tesuji. If white still tries to kill - it's pointless and wastes ko threats/aji, so white shouldn't - but strictly hypothetically...

Click Here To Show Diagram Code
[go]$$Wcm9 The marked stone creates some interesting aji...
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X O X . . . . . |
$$ | . . . . . X . O . . O X X O X X X . . |
$$ | . . . O . . . . . , . . O O . X O X . |
$$ | . . X O . X . O . . . . . . O O . O . |
$$ | . . . O . . . . . . . . . . . . O X . |
$$ | . . X O . X . X O O . . . . . . X . . |
$$ | . O O X . . . . X O . . . . . . . . . |
$$ | . O X X . . . . X O . . . . . . . . . |
$$ | . O X O . . . . X , . . . . . X . . . |
$$ | X O X . . . . . . . . . . . . . . . . |
$$ | 2 X X . X . . . . . . . . . . . O . . |
$$ | 1 O X O X O . . . . . . . . . . . . . |
$$ | . O O X X O . a b . . . . . . . . . . |
$$ | X . O O O X . X c . O . . . . . . . . |
$$ | . O O X O X . X 7 , . . . . . X . . . |
$$ | . O X X X O O O 4 8 O . X . . . . . . |
$$ | O X X . X X x 6 5 . . . . . . . . . . |
$$ | . X . 3 . B . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


As far as I can tell (after 16) white has some moves that almost work, but nothing decisive, because white's three stones only have two liberties now. In a game you'd want to spend awhile reading this carefully.

In practical play, white could exchange 15 for 'c' or 'a' for 'b' or something like that before playing 11. That would prevent the combination I've shown here. However, since black wins the capturing race (shown by topazg) anyway, it doesn't matter. Also, just the fact that white needs to make that sort of makeshift exchange to get by is a gain for black and makes the outside cutting stones more secure.

See the power of preserving aji by not playing 'x'? If you try to play as few moves as are necessary, all sorts of interesting opportunities will appear and your groups will be more flexible and stronger.

Chew Terr wrote:This game wasn't an amazing performance, but it was sure fun to play, and it was cool that it condensed into such a clear-cut tsumego.

Yeah, it's really fun when you start seeing the applications of things you've learned. Keep at it! :)
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