The New Sudoku Players' Forum

[Boisterous Hal]

Please note: Subsequent to posting this message, I solved this puzzle. Thanks to everyone for their support. I encourage everyone to try this puzzle - to me, a Sudoku beginner, it looks tricky at first glance!

This comes from The West Australian newspaper, 30th November 2005, for those playing at home. The difficulty rating is 4 stars out of 5.

7*1|***|2**
8*2|***|*16
*3*|***|***
-----------------
***|4*1|**3
2*4|8*6|5*9
6**|9*7|***
-----------------
***|***|*2*
39*|***|6*1
**5|***|9*4

...where * represents a blank cell.

[emm]

Hello Boisterous Hal - you have reached the judder bars in the puzzle!

Now you have to change tack and look for a hidden single. It’s hidden because there are other numbers in the cell with it but there is no other place it can go in that row, column or box, so it must be the clue for that cell. Hint – this one is in box 7.

Then you’ll find pairs in row 9 – two numbers in only two cells, so they can be removed from other cells in their group.

Then there’s another hidden single.

Then you’re speeding down the home straight!

[Cec]

"...P.S. I have managed to solve the central 3x3 grid and the 3x3 grid to the immediate right of it completely, but not any of the others..."

Hi Boisterous Hal and welcome,
I know you haven't asked but you'll find it easier to define any of these nine 3X3 grids (called 'Boxes' numbered 1 to 9)) and much better explained by clicking on here
Good luck with your sudoku.

Cec

[Boisterous Hal]

IRT em

Thank you for the tip! I applied this tip, and it did work. Finishing the puzzle was a breeze, as you suggested.

IRT cecbevwr

Thank you for directing me to that help message. I will call a 3x3 grid a "box" from now on. :p

Okay guys, thank you for your replies!

[Pat]

Code: Select all

 7 . 1 | . . . | 2 . .
 8 . 2 | . . . | . 1 6
 . 3 . | . . . | . . .
-------+-------+------
 . . . | 4 . 1 | . . 3
 2 . 4 | 8 . 6 | 5 . 9
 6 . . | 9 . 7 | . . .
-------+-------+------
 . . . | . . . | . 2 .
 3 9 . | . . . | 6 . 1
 . . 5 | . . . | 9 . 4

---you’ll find pairs in row 9 – two numbers in only two cells, so they can be removed from other cells in their group.

the early filling of r5
gave me the observation that the 7 for box 9 must go in r7;
this immediately settles the 7 for box 7.

no "pairs" needed;
i'd expect a Medium difficulty-rating.

- Pat

[Animator]

the early filling of r5
gave me the observation that the 7 for box 9 must go in r7;
this immediately settles the 7 for box 7.

no "pairs" needed;
i'd expect a Medium difficulty-rating.

You are correct that you don't need to use 'pairs'.

But you are not so correct about the reason...
The grid that is posted seems to be the starting grid and the hint seems to apply to a later grid.

(I reached the point where I considered using the pair in row 9 aswell, but then I saw that there was only one possibility for the number 3 in box 3. And this removed the need for a pair.)

[Boisterous Hal]

The grid that is posted seems to be the starting grid and the hint seems to apply to a later grid.

The grid posted is the starting grid. I thought it looked tricky from the start, having never encountered a puzzle where two boxes had no starting numbers. I have updated the bold text at the top to reflect this state of mind.

[Pat]

The grid that is posted seems to be the starting grid and the hint seems to apply to a later grid.

The grid posted is the starting grid. I thought it looked tricky from the start, having never encountered a puzzle where two boxes had no starting numbers. I have updated the bold text at the top to reflect this state of mind.

so we're all agreed that the puzzle does not need any pairs?

- Pat