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Re: A 21-clue SE 8.9 Sudoku

Postby m_b_metcalf » Mon Feb 05, 2007 3:45 pm

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

Claudia,
Interestingly, there's a 'loose' cell in this puzzle and, typically, it gets easier going from 21 to 20:
Code: Select all
 . . . . 4 . 1 . 2
 . 7 5 1 . . . . .
 8 . . . . . . . .
 . . . . . 9 . . . SE 2.6
 . . 1 . 3 . 4 . .
 . . . 2 . . . . .
 . . . . . . . . 4
 . . . . . 5 8 7 .
 4 . 6 . 9 . 5 . .

Regards,

Mike Metcalf
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Postby Mauricio » Sat Feb 10, 2007 12:52 am

I saw Equlibrium recently. This sudoku resembles Libria's coat of arms:

Code: Select all
 . . 1 3 8 4 2 . .
 . . . . 2 . . . .
 3 . . . 7 . . . 1
 8 . . . 9 . . . 5
 1 2 3 4 . 6 7 8 9
 6 . . . 1 . . . 4
 9 . . . 6 . . . 2
 . . . . 4 . . . .
 . . 5 1 3 9 6 . .
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Postby m_b_metcalf » Wed Feb 14, 2007 1:52 am

Mauricio wrote:I saw Equlibrium recently. This sudoku resembles Libria's coat of arms:

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


And here's a slightly more challenging variation:
Code: Select all
  . . 8 7 . 9 1 . .
  . . . . 6 . . . .
  5 . . . 2 . . . 4
  2 . . . . . . . 9
  . 5 6 . . . 8 7 .
  4 . . . . . . . 1
  7 . . . 9 . . . 8
  . . . . 4 . . . .
  . . 1 6 . 3 2 . .  SE 8.3

Regards,

Mike Metcalf
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Postby JPF » Wed Feb 21, 2007 10:07 pm

m_b_metcalf wrote:And here's a slightly more challenging variation:
Code: Select all
  . . 8 7 . 9 1 . .
  . . . . 6 . . . .
  5 . . . 2 . . . 4
  2 . . . . . . . 9
  . 5 6 . . . 8 7 .
  4 . . . . . . . 1
  7 . . . 9 . . . 8
  . . . . 4 . . . .
  . . 1 6 . 3 2 . .  SE 8.3

small progress...
Code: Select all
 . . 1 2 . 3 4 . .
 . . . . 5 . . . .
 6 . . . 7 . . . 8
 7 . . . . . . . 3
 . 9 5 . . . 1 7 .
 8 . . . . . . . 4
 2 . . . 3 . . . 5
 . . . . 8 . . . .
 . . 4 5 . 6 7 . .
SE = 8.5

Code: Select all
 . . 1 2 . 3 4 . .
 . . . . 5 . . . .
 6 . . . 7 . . . 8
 7 . . . . . . . 3
 . 9 5 . . . 1 7 .
 8 . . . . . . . 4
 2 . . . 3 . . . 5
 . . . . 8 . . . .
 . . 4 7 . 5 2 . .
SE = 9.0

JPF
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Postby m_b_metcalf » Thu Feb 22, 2007 12:18 am

JPF wrote:small progress...

I tried taking away even more cells:
Code: Select all
 . . 6 3 . 2 9 . .
 . . . . . . . . .
 1 . . . 8 . . . 2
 5 . . . . . . . 1
 . . 7 . . . 6 . .
 2 . . . . . . . 8
 8 . . . 2 . . . 9
 . . . . . . . . .
 . . 3 4 . 6 7 . . non-minimal, SE 5.6 without r1c6

Regards,

Mike Metcalf
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Postby ravel » Thu Feb 22, 2007 2:21 pm

Pattern game?
Code: Select all
 +-------------------+
 | . . 1 2 . 3 4 . . |
 | . . . . . . . . . |
 | 5 . . . 8 . . . 9 |
 | 9 . . . . . . . 5 |
 | . . 6 . . . 2 . . |
 | 1 . . . . . . . 8 |
 | 7 . . . 9 . . . 1 |
 | . . . . . . . . . |
 | . . 2 7 . 4 3 . . |
 +-------------------+ SE 6.7
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Postby m_b_metcalf » Thu Feb 22, 2007 3:25 pm

ravel wrote:Pattern game?

Almost. Curiously, the more cells we remove, the easier it gets:
Code: Select all
 . . 9 7 . . 1 . .
 . . . . . . . . .
 5 . . . 2 . . . .
 2 . . . . . . . 6
 . . 3 . . . 7 . .
 4 . . . . . . . 5
 6 . . . 5 . . . 2
 . . . . . . . . .
 . . 7 1 . 3 9 . .     SE 2.0

18 cells, and not quite symmetric across the anti-diagonal.

Regards,

Mike Metcalf
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Postby ravel » Thu Feb 22, 2007 4:57 pm

Wow, an 18 clue !

This one is nice to solve (x/xy-wing, turbot/sword fish, UR) - r6c1 missing:
Code: Select all
..54.92...........1...8...33.......7..6...4..........87...3...9...........42.65.. SE 6.6

Another minimal:
Code: Select all
..12.34...........5...7...97.......5..6...2..3.......89...5...3...........81.26.. SE 7.2
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Hello back A women's day contribution

Postby claudiarabia » Fri Mar 09, 2007 2:16 am

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

r3c3 is mutable from 5 to 1 giving you SE 2-0

And a tougher puzzle out of this:

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

and a very easy one

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

Good night
Claudia
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Re: Hello back A women's day contribution

Postby m_b_metcalf » Fri Mar 09, 2007 2:49 pm

claudiarabia wrote:Good night
Claudia

Dear Claudia,

Nice to hear from you again. Another:

Code: Select all
 . 1 2 3 . . . . .
 4 . . . 5 . . 9 .
 6 . 7 . 8 . . . .
 8 . . . 7 . . . .
 . 3 5 2 6 . . . 4
 . . . . . . . 1 .
 . . . . . . 7 . .
 . 9 . . . 4 . 3 .
 . . . . 1 . . . 6  SE 9.0

Regards,

Mike Metcalf
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Postby JPF » Fri Mar 09, 2007 2:50 pm

With a similar concept, here are 2 easy puzzles :

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


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


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Postby wapati » Sat Mar 10, 2007 4:36 am

JPF"][quote="m_b_metcalf wrote:And here's a slightly more challenging variation:
Code: Select all
  . . 8 7 . 9 1 . .
  . . . . 6 . . . .
  5 . . . 2 . . . 4
  2 . . . . . . . 9
  . 5 6 . . . 8 7 .
  4 . . . . . . . 1
  7 . . . 9 . . . 8
  . . . . 4 . . . .
  . . 1 6 . 3 2 . .  SE 8.3


There are two puzzles, SE 4.4 or so, with a similar pattern
Code: Select all
. . . | . . . | . . .
. . X | X . X | X . .
. X . | . X . | . X .
---------------------
. X . | . X . | . X .
. . X | X . X | X . .
. X . | . X . | . X .
---------------------
. X . | . X . | . X .
. . X | X . X | X . .
. . . | . . . | . . .

at http://www.sudoku.frihost.net/forum/viewtopic.php?t=2380
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Postby m_b_metcalf » Sat Mar 10, 2007 4:12 pm

wapati wrote:There are two puzzles, SE 4.4 or so, with a similar pattern
Code: Select all
. . . | . . . | . . .
. . X | X . X | X . .
. X . | . X . | . X .
---------------------
. X . | . X . | . X .
. . X | X . X | X . .
. X . | . X . | . X .
---------------------
. X . | . X . | . X .
. . X | X . X | X . .
. . . | . . . | . . .

at http://www.sudoku.frihost.net/forum/viewtopic.php?t=2380

Here's another:
Code: Select all
 . . . . . . . . .
 . . 9 2 . 5 6 . .
 . 7 . . 4 . . 3 .
 . 8 . . 2 . . 6 .
 . . 6 3 . 1 8 . .
 . 9 . . 7 . . 5 .
 . 6 . . 5 . . 2 .
 . . 4 8 . 9 1 . .
 . . . . . . . . . SE 7.2, minimal

Regards,

Mike Metcalf

[Edit 1: it's actually rather a 'loose' pattern. I gave it a quick shake and no fewer than four cells dropped out:
Code: Select all
 . . . . . . . . .
 . . . 1 . 5 9 . .
 . 9 . . . . . 3 .
 . 3 . . 7 . . 6 .
 . . 5 . . . 8 . .
 . 6 . . 8 . . 4 .
 . 7 . . 4 . . 2 .
 . . 2 8 . 9 1 . .
 . . . . . . . . .

Edit 2: Another shake and five dropped out:
Code: Select all
 . . . . . . . . .
 . . 1 2 . 4 . . .
 . 5 . . 6 . . 9 .
 . 3 . . . . . 6 .
 . . . . . 1 4 . .
 . . . . 9 . . 5 .
 . 6 . . 3 . . 7 .
 . . 2 8 . 7 1 . .
 . . . . . . . . .    SE 7.1, 19 cells
]
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Postby JPF » Sat Mar 10, 2007 7:20 pm

could be this one ?

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

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benzol ring

Postby claudiarabia » Sun Mar 11, 2007 12:18 pm

Code: Select all
. 2 6 3 . . . . .
9 . . . 4 . . 6 .
8 . 5 . 7 . . . .
5 . . . 6 . . . .
. 3 7 2 5 . . . 1
. . . . . 3 . 8 .
. . . . . . 2 . .
. 9 . . . 1 . 4 .
. . . . 8 . . . 7 women's day

My solution to womens Day SE 6-7
After the obligatory pointing and single-placement I decided to place the 7 in r2c2 by a regional forcing X-chain. Every candidate of seven in the bottom middle box (r7c46, r8c4) leads by x-subchains to 7 in r2c2. After a UR Type 1 eliminating 23 in r3c9, a string-kite eliminating 1 in r6c3 I and another UR Type 1 eliminating 15 in r7c2 I circumvented the BUG Type 1, which was shown by the Explainer and the puzzle was solved.

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


While looking for the perfect shaped 19er I found out this nice benzol-ring. I'm still working on eliminating r4c4 and r6c6. This sudoku is one of the few SE 8,3-Sudokus which need not so much chains to solve them.

The omission of r6c7 leads to SE rating 8,4 with much more forcing chains.

And here comes Benzol ring SE rating 8,9 minimal:
Code: Select all
. . . 4 . 3 . . .
. 5 . . . . . 7 .
8 . . . 9 . . . 2
. . 2 6 . . 9 . .
7 . . . 5 . . . 6
. . 3 . . 2 4 . .
1 . . . 6 . . . 3
. 4 . . . . . 5 .
. . . 8 . 7 . . .
This number-triple of r4c4, r5c5, r6c6 shapes many sudoku-patterns. It was my last resort moulding the Arabian-Star-puzzle.
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