The New Sudoku Players' Forum

[ChrisHap]

Would very much appreciate a pointer for the next logical move.

*43|98*|25*
6**|425|***
2**|**1|*94
9**|**4|*7*
3**|6*8|***
41*|2*9|**3
82*|5**|***
***|***|**5
534|89*|71*

(17)(4)(3)(9)(8)(67)(2)(5)(167)
(6)(789)(1789)(4)(2)(5)(138)(38)(178)
(2)(578)(578)(37)(367)(1)(68)(9)(4)
(9)(568)(2568)(13)(135)(4)(1568)(7)(1268)
(3)(57)(257)(6)(157)(8)(1459)(24)(129)
(4)(1)(5678)(2)(57)(9)(568)(68)(3)
(8)(2)(1679)(5)(1467)(367)(3469)(346)(69)
(17)(679)(1679)(17)(1467)(2367)(34689)(23468)(5)
(5)(3)(4)(8)(9)(26)(7)(1)(26)

And many thanks in advance for all suggestions.
Chris

[whohe]

Would very much appreciate a pointer for the next logical move.

*43|98*|25*
6**|425|***
2**|**1|*94
9**|**4|*7*
3**|6*8|***
41*|2*9|**3
82*|5**|***
***|***|**5
534|89*|71*

(17)(4)(3)(9)(8)(67)(2)(5)(167)
(6)(789)(1789)(4)(2)(5)(138)(38)(178)
(2)(578)(578)(37)(367)(1)(68)(9)(4)
(9)(568)(2568)(13)(135)(4)(1568)(7)(1268)
(3)(57)(257)(6)(157)(8)(1459)(24)(129)
(4)(1)(5678)(2)(57)(9)(568)(68)(3)
(8)(2)(1679)(5)(1467)(367)(3469)(346)(69)
(17)(679)(1679)(17)(1467)(2367)(34689)(23468)(5)
(5)(3)(4)(8)(9)(26)(7)(1)(26)

And many thanks in advance for all suggestions.
Chris

R1C6&9
R9C6&9

.'. R7C9= ?

[emm]

At the risk of invoking the 'Great Wrath of TSO' can I ask why this puzzle is a 'not verified' in the Sudoku program when it is solveable by simple logic?

[tso]

At the risk of invoking the 'Great Wrath of TSO' can I ask why this puzzle is a 'not verified' in the Sudoku program when it is solveable by simple logic?

Trick question. (I assume you are refereing to Pappocom's Sudoku program when you say "the" Sudoku program. There are many, many other programs.)

1) Pappocom verifies this puzzle without a problem and rates it as "Very Hard". The hardest thing I found was a hidden pair and an x-wing.

2) Many puzzles are 'not verified' by Pappocom that are perfectly solvable by logic -- though probably not "simple" logic, subjective as that term is.

It seems that Pappocom's philosophy is that Sudoku should be solved with a minimum of pencil marks, note taking, line drawing, etc. A puzzle that requires a Swordfish near the end might get a "very hard but arguably unfair" rating, but if a Swordfish were required right at the start, forcing you to fill in 50+ cells with 4, 5 or more pencil marks, it would probably be rejected as "invalid". Difficulty isn't only subjective, it changes depending on what tools or methods are used.

[emm]

I think that's fair enough - I don't want swordfishes either, especially at the start, cos that's the sharp end. Ouch!

[ChrisHap]

Whohe
Thank you for taking the time to point out the X-wing. After that it was plain sailing to the finish. Thanks for your help.
Chris