Thursday, December 26

Solving a super Diabolical Sudoku.

Solving a super Diabolical Sudoku. 
This Sudoku from todays Age Newspaper may haver multiple solutions.  At any rate  I have provided my solution. See if you want to  clear away the Christmas good cheer and put your puzzle solving logic to the test. 
 
Firstly the Puzzle as it appeared in the Age
1
2
3
4
5
6
7
8
9
 
 
 
 
 
 
 
 
 
A
 
 
 3
 
 1
 
 
 9
 
 
 
 
 
 
 
 
B
 
 
 
 
 
 7
 
 
 
 
 
 
 
 
 
 
 
 
C
6
 
 
 9
 
 
 
 
 
 
 
 
 
 
 
 
D
7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
E
 
 
 
 
 
 
 1
 
 
 
 
 
 
 
 
 
F
 
 
4
 
 
 
 
 2
 
 
 
 
 
 
 
 
 
G
 4
 
 
 
 
 
 5
 
 
 
 
 
 
 
 
 
 
H
 
 6
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
I
 
 
 
4
7
 
 
 
My solution 
 
1
2
3
4
5
6
7
8
9
 
 
 
 
 
 
 
 
 
A
8
2
 5
4
 
 
 
 
 
 
 
 
B
9
8
 
 
 
 
 
 
 
 
 
C
6
1
2
8
9
7
 
 
 
 
 
 
 
 
 
D
7
9
6
 1
3
 4
 
 
 
 
 
 
 
 
 
E
5
4
 3
2
 6
 
 
 
 
 
 
 
 
 
F
1
6
4
3
8
 
 
 
 
 
 
 
 
 
G
4
 7
9
3
 1
 6
 
 
 
 
 
 
 
 
 
H
3
 6
7
5
9
 
 
 
 
 
 
 
 
 
I
2
5
8
9
4
7
3
6

3 comments:

Tom said...

Just a quick note, before I attempt my solution. The original puzzle places a 9 in cell C5. Your solution changes that to a 2!! Haven't checked for any further inconsistencies.

Tom said...

After to examples of "Simple Colouring" the solution is:-

287 536 194
915 847 263
634 192 857

728 361 945
543 289 671
196 475 382

479 613 528
362 758 419
851 924 736

I am always deeply suspicious of puzzles from a reputable compiler that appear to have more than one solution. Thus when you said this had multiple solutions, loud alarm bells began to ring. Fun, though!

Lindsay Byrnes said...

Hi Tom
What happened is when I copied the age puzzle to my worksheet I transposed an incorrect number. That is why it appeared to have multiple solutions, and caused me a lot of trouble along the way but it seemed to fit eventually. On the Blog the original puzzle however was recorded correctly, to which there is only one unique solution as per your advice.
I redid the puzzle without using colouring in what was possibly a bit more long winded approach and of course got the same result. Well done for spotting the unintentional error on my part and congratulations on solving the puzzle which I assume you completed fairly easily. Best wishes for the New Year.