X-samurai with only 11+10+6+10+10 clues

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X-samurai with only 11+10+6+10+10 clues

Postby m_b_metcalf » Sun Jan 04, 2015 12:29 pm

Back in the day, ruud found a remarkable 12-clue X-sudoku; strangely enough, it can be solved very easily. Building on that, I have created an X-samurai with a total of only 47 clues, for your enjoyment.

Regards,

Mike Metcalf

Code: Select all
 6 . . . . . 7 . . . . . . . 8 . . . . . .
 . . . . 1 3 . . . . . . . . . 7 4 . . . .
 . . . . . 2 . . . . . . . . . 9 . . . . .
 . . . 7 . . . . . . . . . . . . . 8 . . .
 . . . 4 . . . . . . . . . . . . . 5 . . .
 . 8 . . . . . . . . . . . . . . . . . 2 .
 . . . 5 . . . . . . . . . . . . . 1 . . .
 . 2 . . . . . . . . . . . . . . . . . 9 .
 3 . . . . . . . . . . 5 . . . . . . . . 7
 . . . . . . . . . . . . . 6 . . . . . . .
 . . . . . . . . . . . 7 . . . . . . . . .
 . . . . . . . . . . . 4 . . . . . . . . .
 4 . . . . . . . . . . . . . . . . . . . 1
 . 3 . . . . . . . 9 2 . . . . . . . . 8 .
 . . . 8 . . . . . . . . . . . . . 7 . . .
 . 1 . . . . . . . . . . . . . . . . . 4 .
 . . . 9 . . . . . . . . . . . . . 2 . . .
 . . . 2 . . . . . . . . . . . . . 3 . . .
 . . . . . 3 . . . . . . . . . 8 . . . . .
 . . . . 7 4 . . . . . . . . . 1 9 . . . .
 . . . . . . 2 . . . . . . . 3 . . . . . .


Code: Select all
600000700000013000000002000000700000000400000080000000000500000020000000300000000  TL
008000000000740000000900000000008000000005000000000020000001000000000090000000007  TR
000000000000000000000005000000000060000007000000004000000000000000920000000000000  M
400000000030000000000800000010000000000900000000200000000003000000074000000000200  BL
000000001000000080000007000000000040000002000000003000000800000000190000003000000  BR
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m_b_metcalf
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Re: X-samurai with only 11+10+6+10+10 clues

Postby enxio27 » Sun Jan 04, 2015 4:18 pm

Interesting! Any idea of a difficulty rating on this one?
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Re: X-samurai with only 11+10+6+10+10 clues

Postby m_b_metcalf » Sun Jan 04, 2015 8:37 pm

enxio27 wrote:Interesting! Any idea of a difficulty rating on this one?


Yes, but the answer is more complex than usual, so I'll delay answering until you've had a chance to solve it yourself.

Regards,

Mike Metcalf
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Re: X-samurai with only 11+10+6+10+10 clues

Postby m_b_metcalf » Tue Jan 06, 2015 7:49 am

m_b_metcalf wrote:
enxio27 wrote:Interesting! Any idea of a difficulty rating on this one?


Yes, but the answer is more complex than usual, so I'll delay answering until you've had a chance to solve it yourself.

Basically, an SE rating would be in the range 7 to 8. However, if one gets stuck there are other possibilities beyond the usual rules of sudoku. One is hidden below.

Regards,

Mike Metcalf

Hidden Text: Show
As stated, the basis of this puzzle is the 12-clue puzzle of ruud. As there is only one of these, the five individual puzzles must each be a subset of an isomorph of the 12-clue one. Finding the (simple) transformation used between any pair of them enables additional clues to be added.
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Re: X-samurai with only 11+10+6+10+10 clues

Postby enxio27 » Tue Jan 06, 2015 6:13 pm

m_b_metcalf wrote:Basically, an SE rating would be in the range 7 to 8.

:o :oops: (where's that color-draining-from-face smilie when we need it?) This one may be out of my league. I think an SE rating of 4.0 is about my limit right now.

However, if one gets stuck there are other possibilities beyond the usual rules of sudoku. One is hidden below.

Thanks! I'll use it as a last resort. I've started the puzzle--found some easy naked doubles and triples, but not even one elimination in the overlap areas.
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Re: X-samurai with only 11+10+6+10+10 clues

Postby enxio27 » Mon Jan 19, 2015 9:04 pm

I just figured out why I was having difficulty with this puzzle. When I transferred it to Richard Broughton's Sudoku Solver for pencil marks and printing, I failed to mark it as a Sudoku-X instead of vanilla. Going much better now. And I'm definitely seeing a pattern as I solve. . . ;)
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