## Every puzzle has just one correct solution?

All about puzzles in newspapers, magazines, and books

### Every puzzle has just one correct solution?

I'm a newbie - sudoku has just started appearing in my local newpaper - NY Newsday. The very first puzzle (07/25/2005) published appears to have more than one solution? Can someone verify and let me know if i'm just making a newbie mistake? Thanks!

Original Puzzle

Code: Select all
`. . 5 | . . 4 | . 6 .. . . | 2 . 6 | 1 . .4 . . | . . 5 | . . 7---------------------7 . . | . . 2 | 8 . .. . 9 | . 6 . | 5 . .. . 3 | 8 . . | . . 6---------------------1 . . | 6 . . | . . .. . 2 | 7 . 9 | . . 4. 9 . | 1 . . | 6 . .`

Solution printed in newspaper (next day)
Code: Select all
`9 7 5 | 3 1 4 | 2 6 84 3 8 | 2 7 6 | 1 5 92 6 1 | 9 8 5 | 4 3 7---------------------7 4 6 | 5 3 2 | 8 9 18 1 9 | 4 6 7 | 5 2 35 2 3 | 8 9 1 | 7 4 6---------------------1 5 7 | 6 4 3 | 9 8 26 8 2 | 7 5 9 | 3 1 43 9 4 | 1 2 8 | 6 7 5`

My solution
Code: Select all
`2 7 5 | 3 1 4 | 9 6 89 3 8 | 2 7 6 | 1 4 54 6 1 | 9 8 5 | 2 3 7---------------------7 4 6 | 5 3 2 | 8 9 18 2 9 | 4 6 1 | 5 7 35 1 3 | 8 9 7 | 4 2 6---------------------1 5 4 | 6 2 3 | 7 8 96 8 2 | 7 5 9 | 3 1 43 9 7 | 1 4 8 | 6 5 2`

Thanks for any comments / corrections...

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winmine2

Posts: 2
Joined: 26 July 2005

### Re: Every puzzle has just one correct solution?

winmine2 wrote:Can someone verify and let me know if i'm just making a newbie mistake?

Hi winmine2.

Well, it looks like someone made a mistake, are you sure you copied it correctly? The puzzle you posted is slightly asymmetrical, so if you move the 4 at (3,1) to (2,1) as shown below the puzzle completes with a single solution.

Code: Select all
`. . 5 | . . 4 | . 6 . 4 . . | 2 . 6 | 1 . . . . . | . . 5 | . . 7 --------------------- 7 . . | . . 2 | 8 . . . . 9 | . 6 . | 5 . . . . 3 | 8 . . | . . 6 --------------------- 1 . . | 6 . . | . . . . . 2 | 7 . 9 | . . 4 . 9 . | 1 . . | 6 . . `
angusj

Posts: 306
Joined: 12 June 2005

thanks angusj,
I will check to see if I've entered the correct input puzzle (when i get to work tomorrow)- but, the rules at http://sudoku.com/rule.htm say that Every puzzle has just one correct solution". Either the statment is incorrect, or the puzzle is invalid? (can a puzzle be invalid?) thoughts?
winmine2

Posts: 2
Joined: 26 July 2005

If you check the solution quoted from the paper, then you will see that, as angusj says, there should be a 4 at 3,1 rather than 2,1. It's really down to whether the error was in the paper or in the copying!
ArchieB

Posts: 9
Joined: 22 May 2005