help with expert sudoko puzzle

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help with expert sudoko puzzle

Postby nadav3 » Mon Aug 12, 2013 7:14 pm

hello
I'm learning advanced techniques to solving sudoko puzzles.
I'm stuck with this one, I've tried anything I know (hidden singles, naked pairs, triples and quads, x-wing) and still cannot find the next move.
can someone enlighten me?
the pencil marks shown are after I narrowed down the options.
thank you :)
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Re: help with expert sudoko puzzle

Postby JasonLion » Tue Aug 13, 2013 2:39 am

I see a locked candidate on 5 in row 6, and then singles to the end.
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Postby Pat » Tue Aug 13, 2013 6:55 am


    (5) b1\c2
    solves the 5 for r6
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Re: help with expert sudoko puzzle

Postby nadav3 » Tue Aug 13, 2013 7:17 am

thanks a lot... don't know how I didn't see it...
Pat, what does this mean in words: (5) b1\c2 ?
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Re: help with expert sudoko puzzle

Postby JasonLion » Tue Aug 13, 2013 11:43 am

Pat was pointing out a different locked candidate, digit 5 in block 1 which eliminates 5s in the rest of column 2, and also solves the puzzle with singles to the end.
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Re: help with expert sudoko puzzle

Postby nadav3 » Tue Aug 13, 2013 12:30 pm

thanks, I don't understand how I missed that... :)
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Postby Pat » Mon Aug 19, 2013 12:11 pm


  1. box\line: (5) b1\c2 --> r6 5
  2. line\box: (5) c3\b4 --> r6 5
  3. line\box: (5) r6\b4 --> c3 5 [ path suggested by JasonLion ]

    the symmetry between b and c
    makes me reluctant to prefer one over the other,
    so how about going to a fish of order 2:

  4. X-wing: (5) r6c3\b44 --> b4 5
    [ one of those bizzare beasts with same house twice in the cover ]
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