## tough sudoku collection

Post puzzles for others to solve here.

### Re: tough sudoku collection

David P Bird wrote:docjohn,
Congratulations on your efforts. However, to pick up on one point in your definitions; what you call a strong link is actually a conjugate link. With a strong link it is possible for both the linked terms to be true. I haven't checked if this affects any of your other tutorial pages though. See the <AIC Primer Thread>

David PB
.

Thanks Dave. I haven't heard of a conjugate link before. Hopefully I'll learn something here. Thanks for the feedback
docjohn

Posts: 25
Joined: 07 January 2011

### Re: tough sudoku collection

But I don't understand why docJohn says it's unsolvable. I thought I showed a solution and that others confirmed the solution.

Marty, I stand corrected. It is indeed a solvable puzzle. My solver (Jet Sudoku) was using a unique rectangle technique incorrectly and creating a false dead end.
Looks like I have some debugging to do.
docjohn

Posts: 25
Joined: 07 January 2011

### Re: tough sudoku collection # 2

Code: Select all
`+-----------------+--------------------+------------------------+| 6     9      8  | 5      7       4   | 1        2       3     || 7     2      4  | 19     389     139 | 569      69      5689  || 1     3      5  | 6     b89      2   | 7        4      a89    |+-----------------+--------------------+------------------------+| 9     7      1  | 3      2       56  | 56       8       4     || 8     5      26 | 4     c69      7   | 3        1      f269   || 3     4      26 | 8      1      d569 |e2569    e679    e25679 |+-----------------+--------------------+------------------------+| 4     16     3  | 19     5       8   | 269      679     2679  || 2     8      9  | 7      36      36  | 4        5       1     || 5     16     7  | 2      4       19  | 8        3       6-9   |+-----------------+--------------------+------------------------+`

(9=8)r3c9 - (8=9)r3c5 - r5c5 = r6c6 - r6c789 = (9)r5c9 => - 9r9c9; stte

Clement
Ngisa

Posts: 852
Joined: 18 November 2012

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