The New Sudoku Players' Forum

[marland]

Ok I read the site about the UR.. and they constantly talk about

"otherwise we could swap the <1> & <2> and still have a valid solution, which is not allowed"

As I understand it correctly it isnt allowed because the sudoku wouldt be valid? so, if you were able to swap the numbers the sudoku isnt genuine.. or "bona fide"? because I dont see amother reason why swapping isnt allowed..

Ill remember the rule for my future sudoku carriere.

Oh and I still have much troube understanding Why the A's share a group.. why isnt the B in that group? ... I mean when do they share a group?
If I make an random A 1 than the puzzle is correct (well only for the 1s), right?

Im very gratefull for your patience. Thanks again!

[emm]

Oh and I still have much troube understanding Why the A's share a group.. why isnt the B in that group? ... I mean when do they share a group? If I make an random A 1 than the puzzle is correct (well only for the 1s), right?

Code: Select all

 
*-----------------------------------------------------------*
 | 3     7     2     | 159   589   18    | 4     6     19A   |
 | 4     56    56    | 7     359   13A   | 19B   8     2     |
 | 9     8     1     | 4     2     6     | 3     5     7     |
 |-------------------+-------------------+-------------------|
 | 8     19A   3     | 6     4     5     | 2     7     19B   |
 | 2     49    7     | 13    38    138   | 6     49    5     |
 | 16A   1456  56    | 2     7     9     | 8     14A   3     |
 |-------------------+-------------------+-------------------|
 | 7     3     9     | 8     1     4     | 5     2     6     |
 | 5     16A   8     | 39    369   2     | 7     19B   4     |
 | 16B   2     4     | 59    569   7     | 19A   3     8     |
 *-----------------------------------------------------------*



I think this relates back to the colouring.

A group is a row, column or box. If after colouring you end up with two of the same label ( A or B) in the same group then all candidates of that label are eliminated.

In this case there are 2 As in box 4, in row 6 and in column 2 => all cells labelled A do not equal 1.

[marland]

Ohhhh now I understand. this is a nice trick.. this colouring. Its hard to do it in your head so you really need to make pencilmarks but other than that its a nice trick.

I love sudoku again.

Thanks