The New Sudoku Players' Forum

[bigbird]

Hi, new on the forum and a cry for help!

I am stuck with this one:

485 9.. 1.6
731 ..6 95.
962 5.. 4..

..8 ..4 3..
6.4 398 5.1
..3 1.. 8.4

847 639 215
.59 ... 683
3.6 ... 749

Can anybody give me the logic clue? I have been reading some of the postings, and I guess some of you are using computer solvers? I would be impressed when somebody would "see" the clue without computer help.

Anyway, I can always look up the solution in the back of the puzzle book, but that would be a bummer....

[CathyW]

This one would be very difficult without guessing - according to Sadman software it has 5 solutions.

[ukodus99]

R2C9 the only available value is 2.

After that, r4c9 is obvious, as will be a lot more values, until you get to pairs in all boxes except 1 and 9 where all box values will be filled in.

At that point, dealing with the pairs in box 7, I chose one of the values and saw the game through to its successful conclusion.

[emm]

It sounds to me like ukudos99 is quoting Sudoku Susser.

Bigbird, this puzzle is invalid. Even the computers can't solve it by logical techniques - it has more than one solution and you'll end up having to guess. You need to find a reliable source of one solution puzzles - like Pappocom! Click there!

[Shazbot]

R2C9 the only available value is 2.

How did you work that out? R2C9 and R3C9 have 2 and 8 as candidates - I don't see any way to eliminate the 8 from R2C9.

[bigbird]

R2C9 the only available value is 2.

How did you work that out? R2C9 and R3C9 have 2 and 8 as candidates - I don't see any way to eliminate the 8 from R2C9.

In fact, the "solution" (as it thus appears one of the 5) for this cell in the back of the puzzle book is 8!

[QBasicMac]

Anyway, I can always look up the solution in the back of the puzzle book, but that would be a bummer....

LOL! I wondered if anyone ever looked at those.

No need. Even in worst case, you can use T&E

1) Solve as far as you can
2) Save the puzzle (or copy it, if manual)
3) Pick a cell and make a list of it's candidates
4) Try each candidate

All candidates but one must lead to a invalid position or the puzzle has multiple solutions and is bogus and the source of the puzzle should no longer be used (unless - as is often the case - you copied it incorrectly)

If your trial also gets stuck, you have to recursively do T&E. Make another copy, pick another cell, etc.

Mac

[masb]

There are two solutions and R2C9 can be 2 or 8 but 8 gives the simpler solution. I used my solving tool to determine this (see http://www.axcis.com.au/bb/viewtopic.php?t=25).

The two solutions are:

485973126
731246958
962581437
198754362
624398571
573162894
847639215
259417683
316825749

and

485972136
731486952
962513478
198254367
674398521
523167894
847639215
259741683
316825749

[QBasicMac]

There are two solutions

At least! Here is another one I reached by T&E

Code: Select all

485 923 176
731 486 952
962 571 438
518 264 397
674 398 521
293 157 864
847 639 215
159 742 683
326 815 749


Mac

[simes]

Code: Select all

485923176731486952962517438518264397674398521293175864847639215159742683326851749
485923176731486952962571438518264397674398521293157864847639215159742683326815749
485927136731486952962513478518264397674398521293175864847639215159742683326851749
485972136731486952962513478198254367674398521523167894847639215259741683316825749
485973126731246958962581437198754362624398571573162894847639215259417683316825749

Like Cathy says, there are 5 solutions from the position you give. Are you sure didn't make a mistake posting the puzzle?

S