Doomed stones?

Inkwolf · Post by **Inkwolf** » Tue Oct 04, 2011 9:50 am

Do you think here was any way to save the upper right after move 101? I didn't see one, so I left it alone (mostly) but can't help feeling I gave up too soon on it.

Horibe · Post by **Horibe** » Tue Oct 04, 2011 9:56 am

I would try k15.

Inkwolf · Post by **Inkwolf** » Tue Oct 04, 2011 10:01 am

Horibe wrote:I would try k15.

!!!!!!!!!!!!!!!!

How did I miss the perfect moment for that? Probably because I kept thinking I'd have to connect at M19 before playing N19. Ack! I totally missed what would probably have been the winning move.

Thanks, I'll go bang my head on the desk for a while.

daniel_the_smith · Post by **daniel_the_smith** » Tue Oct 04, 2011 10:19 am

See var for move 99:

EDIT: I just realized that you're black. Sorry! 90 is the problem, it should be at O18.

Inkwolf · Post by **Inkwolf** » Tue Oct 04, 2011 10:28 am

daniel_the_smith wrote:See var for move 99:

EDIT: I just realized that you're black. Sorry! 90 is the problem, it should be at O18.

I agree, thanks. The potential move you showed at 99 was one of the reasons I decided the upper right was beyond rescue.

Bill Spight · Post by **Bill Spight** » Tue Oct 04, 2011 10:59 am

As usual, the problem actually arises earlier. See hint.

I have shown some variations for White. (Black may not always make the best reply.

)

Edit: I see that Daniel the Smith partly beat me to the punch.

Inkwolf · Post by **Inkwolf** » Tue Oct 04, 2011 11:16 am

Bill Spight wrote:As usual, the problem actually arises earlier. See hint.

L15, I guess. Sigh...I let White have a clear path right down the middle of my formation.

jts · Post by **jts** » Tue Oct 04, 2011 11:17 am

There's a good general principle here - there are some moves (like o19 in that situation) which count as an extra liberty because they require one (or more) approach moves, but only when there are two or more of them. If you play o19 immediately you would be in atari so it seems that you need to connect at m19 first (and indeed once you've connected at m19, he can play at l18 and force you to capture that before finally playing o19), but instead you can put him into atari first, and capture by playing the "self-atari" liberty.

The same logic extends to eyes and ko -- eyes, kos, and moves that would be self-atari are all moves that you would prefer to take last, as the capturing move, but obviously if there are more than one of them that's not possible, and so they make the capture harder by forcing you to make approach moves and/or fight a ko.

Website · Post by **Chew Terr** » Tue Oct 04, 2011 11:18 am

Inkwolf wrote:
Bill Spight wrote:As usual, the problem actually arises earlier. See hint.

L15, I guess. Sigh...I let White have a clear path right down the middle of my formation.

Perhaps, but remember: the next game is more important than this game. Because of this game, you won't do it again next game, or the one after that.

Life In 19x19

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