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Clement · Posted: Sun Nov 11, 2012 5:58 pm Post subject: Menneske6905337

They should be as publihed.

TNova · Joined: 17 Jul 2012 Posts: 16 Location: Bromley, UK

Hi Ffred,

Thanks for posting these puzzles, but this one has 210 solutions! Can you please recheck.

Tim

Clement · Posted: Mon Nov 12, 2012 12:18 pm Post subject: Menneske 6905337

The original puzzle is like this

Marty R. · Posted: Mon Nov 12, 2012 7:32 pm Post subject: Re: Menneske6905337

Marty R. · Posted: Tue Nov 13, 2012 12:45 am Post subject:

Ffred,

Maybe next time you could select a puzzle more in line with our talents? Very Happy

Showing puzzle number: 6905337
Puzzletype: Optimal Sudoku
Startnumbers: 24
Difficulty: Impossible (3389)

ffred · Joined: 29 Oct 2012 Posts: 19 Location: Kent, Egland

Many apologies for the mistakes. I was copying from my 'post-basic' sheet & (a) forgot that a couple of 4s had been filled in (b) very carelessly left out a 3. (I promise that if I post again I'll be super careful, having absorbed the lesson that it pays not to work needlessly fast.)

Sorry Marty. I thought that this was about right based on the sorts of puzzles I've seen posted - harder than some, easier than others. (I've done dozens, maybe hundreds of these Menneske Impossibles. A few turned out to be too easy - e.g. just one XY-wing needed. A few turned out to be too difficult for me. Most, like this one, are somewhere in between.)

Here's the position after basics:-

ffred · Joined: 29 Oct 2012 Posts: 19 Location: Kent, Egland

PS 1. Hi Tim, thanks for pointing out the mistake. I see that you too use Andrew Stuart's excellent program! (It's maybe a bit lazy, but I often use it to dash through the basics, print out that sheet and work from there. I still like doing basics-only sudokus once a week in my Sunday paper. The Hard just needs you to spot a hidden pair or something like that - fun to do without writing in candidates. But it seems a waste of time when I'm doing a difficult puzzle.)

PS 2. Marty, you were one of my heros/gurus about 5 yrs ago: I learnt how to make deductions about URs etc. from your posts. So it seems very strange to be offering advice: I hope that you're not offended. Here goes. Before I was really comfortable with Eureka I used to mark an F for false under the starting candidate, the 8 in r2c3 in the grid above. That fixes the 8 in r2c1 as a T for true, and you can therefore put an F under the 1 in that cell. That makes the 1 in r2c6 a T. And so on. You end up with a the 8 in r6c4 being a T. Then it's easy to translate into Eureka. Going from F to T is a strong link, an =. Going from T to F is a weak link, a -.

SudoQ · Joined: 02 Aug 2011 Posts: 127

Marty R. · Posted: Tue Nov 13, 2012 3:52 pm Post subject:

[quote="SudoQ"][code]r2c1=8 -> r2c6=1 -> r5c4=1 -> r5c9=8 ->
-> -> r6c4=8 -> r6c23=7 => r2c1<8> r5c9=8. What I'm seeing superficially is that r5c4=1 -> a 268 triple in r5.

Thanks.

Marty R. · Posted: Tue Nov 13, 2012 3:53 pm Post subject:

keith · Posted: Tue Nov 13, 2012 6:39 pm Post subject:

SudoQ · Joined: 02 Aug 2011 Posts: 127

Marty R. · Posted: Wed Nov 14, 2012 1:20 am Post subject:

Thanks. It's the rule, not the exception, that I miss that kind of stuff. Embarassed