# Problem solution ? [#3047]

Timm: Problem solution ? (2014-07-28 23:47) [#10190]

Hi SL,

Black to kill unconditionally

A friend of mine has submitted me the following problem. It's supposed to be easy but there's a part we actually couldn't solve despite spending some time on it.

Black to kill unconditionally

This was the solution given for the problem.

Black to kill unconditionally

However, after this we didn't manage to kill White unconditionally anymore. As compared with the diagram above, the absence of the a-b exchange gives White more possibilities.

Unfortunately this variation wasn't described in the solution. In the end we think there's an issue with the problem but we're probably wrong :-) there must be something we haven't seen and I'd be very glad if someone pointed it out.

Best,

78.22.73.129: ((no subject)) (2014-07-29 00:14) [#10191]

If there is a black stone eg two below the bottom left black stone then black can still kill by pushing in and next Atari at the other side.

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Timm: Re: ((no subject)) (2014-07-29 13:37) [#10192]
Black to kill unconditionally

This..?

Dieter: answering timm (2014-07-29 13:45) [#10193]

Without the stone, Whhite can push through at a.

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Timm: Re: answering timm (2014-07-29 15:14) [#10194]

Yes but this is a ko, isn't it ? The problem asks for an unconditional kill.

tapir: Re: answering timm (2014-07-29 15:19) [#10195]

No ko, imagine White "starting the ko", Black simply connecting . How many eyes does White have?

Timm: Re: answering timm (2014-07-29 16:35) [#10197]

Indeed ! I think that's what I was missing.

Dieter: ((no subject)) (2014-07-29 16:27) [#10196]
Missing stone

In any case a stone is missing. After the more straightforward -, White can move out. There must be some defense for that marked stone. The option of moving out cannot be accepted in a common L&D problem.

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Timm: Re: ((no subject)) (2014-07-29 16:35) [#10198]

Probably so ; I'll check with my friend. Sorry if I made a mistake. Anyway, thanks all for your answers. Timm