The New Sudoku Players' Forum

[Guest]

Hello all. I wonder if you could help. I can't get any further with the Fiendish number 100. I got as far as the following:

Code: Select all

**2|**9|*64
*64|*25|**9
*3*|6**|2**
-----------
6**|2**|*4*
*4*|***|***
*7*|**3|**1
-----------
315|**2|97*
49*|13*|5**
82*|59*|413

I can look up the solution but that will not show me the way forward, only the end result. I would appreciate it if you could give me an idea!!! Thanks. Cris

[shakers]

Knowing that there is only one value that r4c3 can be should get you going again.

[Guest]

I'm sorry Shakers, I looked at it and looked and looked and can't work out what number should go in there.
Could you give some more guidance please? Thank you.

Cris

[shakers]

I'm sorry Shakers, I looked at it and looked and looked and can't work out what number should go in there.
Could you give some more guidance please? Thank you.

Cris

If you have a look at row 4, there's only one place that a 9 can go... r4c3.

Or, if you're more vertically inclined, have a look at col 2, there are two missing values (r1c2 and r4c2) and the possible numbers are 5 and 8. r4c2 cannot be an 8 as there's already an 8 in box 4.

[Guest]

I don't quite understand what shakers is trying to get at in his last post as I can't see the 8 in box 4, however he is correct as regards the 9. Check along row 4 and you should see it.

Similarly consider where 4 can go in column 6.

[shakers]

I don't quite understand what shakers is trying to get at in his last post as I can't see the 8 in box 4, however he is correct as regards the 9. Check along row 4 and you should see it.

Similarly consider where 4 can go in column 6.

Mea culpa - I placed the 8 in r6c3 after fixing the 9 in r4c3 (as fixing the 9 left no other option for r6c3). It had remained it in place when I was reworking the puzzle to try and explain.

Trying to unpick these things is quite a horrid task!

[Guest]

Thank you shakers for your patience, your advice has been most helpful. I have now resolved the fiendish puzzle.

Regards,
Cris

[Guest]

Row 4:

6 * * | 2 * * | * 4 *

Numbers that are missing: 1, 3, 5, 7, 8, 9

If you check where each number can go then you get:

6 5/8? 1/3/8/9? | 2 1/5/7/8? 1/7/8? | 3/7/8? 4 5/7/8?

As you can see the only valid position to put the 9 on row 4 is in column 3.

Reason:
column 1: no 9, but the cell is fixed with 6
column 2: 9 at row 8
column 3: no 9
column 4: no 9, but the cell is fixed with 2
column 5: 9 at row 9
column 6: 9 at row 1
column 7: 9 at row 7
column 8: no 9, but the cell is fixed with 4
column 9: 9 at row 2

So the only columns that can have a 9 are 1, 3, 4, 8, but all except 3 are already filled in.