The New Sudoku Players' Forum

by **Sudoku Snoopy** » Mon Nov 28, 2005 12:22 pm

Pretty happy to have found this forum. I've been sweating over this puzzle for 3 days now, I have the final solution, but not the resolution details (64979). I'm stuck. So stuck...

I thought I was good at Sudoku, so is this a really difficult one ?

x x x 6 x x 4 9 7
x 9 x x x x x x 8
x x x x x 7 x x 3
x x x 7 x x 9 8 2
x x x 2 x 4 x x 1
x 2 1 x x 6 x x x
4 1 x 5 x x x x x
5 x x x x x x 1 x
2 7 6 x x 3 x x x

I have pencil marks all over the place and have only managed to find the 3 numbers in red. Any idea someone ?
Thanks from snowy Switzerland!

by **rubylips** » Mon Nov 28, 2005 12:33 pm

Snoopy,

You have to learn about Block and Column/Row Interactions. A very good guide to the basic Sudoku techniques is provided by simes.

No snow in London yet this winter.

by **Sudoku Snoopy** » Mon Nov 28, 2005 12:34 pm

Come to think of it, this may not be the right place to submit my post... If so, can someone let me know?

by **rubylips** » Mon Nov 28, 2005 1:01 pm

People commonly post puzzles they can't solve to the Solving Techniques forum. The only point I'd make is that several Sudoku solvers are available for free on the Web. You might find it easier to use some of this software than to post to the website.

by **stuartn** » Mon Nov 28, 2005 1:14 pm

The position of the 6's in box 6 allows you to remove some candidates from box 4. Then look at the 9's in box 7.

stuartn (still not snowing in London)

by **Sudoku Snoopy** » Mon Nov 28, 2005 2:41 pm

thanks stuart. Then what ? Those were the only pencil marks I managed to remove. Line 4: 6 is necessarily in column 1 or 2. Line 5: 6 in column 7 or 8. Column3: 9 in line 7 or 8...
I must be missing something obvious...

by **rubylips** » Mon Nov 28, 2005 3:16 pm

It sounds as though you'd like more than just hints ...

Code: Select all: The value 6 in Box 4 must lie in Row 4. - The moves r5c1:=6 and r5c2:=6 have been eliminated. The value 6 in Box 9 must lie in Column 9. - The moves r7c7:=6, r7c8:=6 and r8c7:=6 have been eliminated. The value 9 in Box 4 must lie in Column 1. - The move r5c3:=9 has been eliminated. The value 9 in Box 8 must lie in Column 6. - The moves r7c5:=9, r8c4:=9, r8c5:=9, r9c4:=9 and r9c5:=9 have been eliminated. The cell r9c9 is the only candidate for the value 9 in Row 9.

by **Sudoku Snoopy** » Mon Nov 28, 2005 3:21 pm

Thanks to both. Promise i won't ask for more.

by **Sudoku Snoopy** » Mon Nov 28, 2005 3:30 pm

Ah haa... Got it... I had missed the "The value 9 in Box 8 must lie in Column 6. " bit... Can't believe I hadn't see it.

thanks heaps.

by **QBasicMac** » Mon Nov 28, 2005 3:35 pm

If you want detailed answer

Mac

Locked candidate 6 in box 6
- r5c78 have the only two 6's in box 6.
- But they are both in row 5
- Therefore any other pencilmarks 6 in row 5 can be erased
- r5c1: {36789} >> {3789}
- r5c2 {3568} >> {358}
Locked candidate 9 in box 7
- Similar
Locked candidate 9 in column 6
- r78c6 have the only pencilmarks 9 in column 6 and they are in the same box
- This means you can erase pencilmark 9 from all cells in box 8 except for the two.
Locked candidate 6 in column 9
- This clears three pencilmark 6 from box 9
Hidden single 9 in row 9
- Only r9c9 has a 9 on that row. Thus r9c9=9

by **Sudoku Snoopy** » Mon Nov 28, 2005 3:46 pm

Finished it! Hurrah!!!

(it has stopped snowing by the way...)

The New Sudoku Players' Forum

Help Snoopy find the solution to this diabolical Puzzle

Help Snoopy find the solution to this diabolical Puzzle