The New Sudoku Players' Forum

[asajar]

I got this puzzle to the following state:

Code: Select all

*-----------------------------------------------------------*
 | 5     3     28    | 249   2789  289   | 1     47    6     |
 | 47    6     9     | 1     3     5     | 478   2     48    |
 | 247   14    128   | 24    278   6     | 3     5     9     |
 |-------------------+-------------------+-------------------|
 | 24    49    5     | 3     249   7     | 4689  168   18    |
 | 8     149   12    | 6     5     249   | 49    3     7     |
 | 3     7     6     | 8     49    1     | 5     49    2     |
 |-------------------+-------------------+-------------------|
 | 1     2     3     | 7     489   489   | 4689  4689  5     |
 | 9     8     7     | 5     6     34    | 2     14    134   |
 | 6     5     4     | 29    1     2389  | 789   789   38    |
 *-----------------------------------------------------------*

I thought I had an XYZ wing formed by r4c1, r4c5,r6c5 thereby being able to eliminate the 4 at r4c2. This is not correct since r4c2 is a 4. Can someone please explain why this is not an xyz wing pattern? Thanks for any help with this one.

[daj95376]

You can only eliminate 4 in cells that see all three cells; i.e., [r4c4] and [r4c6]. However, 4 has already been eliminated from these cells. On the other hand, what about cells [r3c1]/[r2c1]+[r3c4]?

[Luke]

Or get naked in r4....

[asajar]

Thank you for your help--I now fully understand the concept.