Can Black Kill? [#3077]

216.125.49.252: Can Black Kill? (2014-10-30 20:58) [#10282]

What is the best possible outcome for Black?

Black to Move
50.185.62.36: ((no subject)) (2014-10-31 19:17) [#10283]

I think the B 18 clamp kills

X
73.8.21.124: Re: ((no subject)) (2014-11-01 21:38) [#10285]

Thanks! I think you are right. I did not find that move in my actual game. -Dent

Timm: Re: ((no subject)) (2014-11-02 19:26) [#10286]
End position

216.125.49.252: Re: ((no subject)) (2014-11-03 23:45) [#10288]

This looks like white lives, but is 5 necessary to kill? If black connects in the corner with 5, can white make two eyes on the right? I would guess that maybe white 6 at 5 would then be alive?

In the actual game, I played 1 at 3 (hane) with the obvious response at 6, then 3 at either 4 or 5(?) I eventually killed but I am convinced white made mistakes. Both white and I were (are) low level players.

Dieter: Re: ((no subject)) (2014-11-04 11:40) [#10289]

I would guess that maybe white 6 at 5 would then be alive?

Dieter: I could answer this but I think it is better for you to read it out then make a firm statement.

Timm: Re: ((no subject)) (2014-11-05 13:05) [#10290]

What happens after White's descent is indeed a cool kyu-level problem.

End position

The first thing to note is that if Black saves his corner stones with , White will be able to live on the right.

@

More interesting is to note that even with , White doesn't have an eye in the corner yet : Black can fill with at , then captures and can be at again.

No eye yet

Now Black threatens to play and remove the eye in the corner (after White captures the two stones Black throws-in at again and it's a false eye), therefore White must play at herself to complete the eye — in gote.

Thus to live she must first complete a first eye in sente on the right. I let you figure out if that's possible ;)

p.s. For , Black should also try the hane (at a in the second diagram). Always try the hane ! :p

73.8.21.124: Re: ((no subject)) (2014-11-06 06:51) [#10292]

Okay, I'll give it a shot...

Sente

I think this lives because if connects at 'a', at 'b' makes two eyes, one at E19 where black is eventually captured and one at F18. Black at b just loses the corner group and white must eventually capture the invading stones for a second eye.

Can't prevent an eye on the right with 2 at 'b'
Can't Falsify F18 after 3 at 'b'
Timm: Re: ((no subject)) (2014-11-06 15:56) [#10293]

Yep, that's what I read. :)

Now regarding the Hane — following the proverb Hane, Cut, Placement, the hane is usually a working killing technique.

The hane

lives, because White's able to make a second eye at either a or b.

The hane

Black can't play a

Finally, given that white's alive and the clamp is bound to be gote, I think that this is the correct endgame play.

Endgame

The area around a is gote for Black so White's likely to have to play there first. Then allows to close off the middle without too much bad aji.

Endgame
Endgame

Without the marked exchange, White can create resist with and and create a lot of trouble...