I would like some to explain the next step for me. I use the Simple Sudoku program and the Hint tells me about an X-Y Wing eliminating (I think) the 2 in R5, C9. XY Wing isn't discussed in the Help topics.
Thanks in advance:
*-----------*
|..1|.2.|.53|
|.4.|5.1|..6|
|.25|7..|..1|
|---+---+---|
|..6|.8.|...|
|..3|.1.|9..|
|...|.4.|5..|
|---+---+---|
|5.4|..2|.7.|
|8.7|.53|.4.|
|9.2|.7.|1..|
*-----------*
*-----------*
|..1|.2.|.53|
|.4.|5.1|..6|
|.25|7..|..1|
|---+---+---|
|..6|.8.|3..|
|..3|.1.|9..|
|...|34.|5..|
|---+---+---|
|534|1.2|.7.|
|817|.53|.4.|
|962|.7.|135|
*-----------*
*-----------------------------------------------------------*
| 67 89 1 | 48 2 4689 | 478 5 3 |
| 37 4 89 | 5 39 1 | 278 289 6 |
| 36 2 5 | 7 369 4689 | 48 89 1 |
|-------------------+-------------------+-------------------|
| 124 57 6 | 29 8 579 | 3 12 247 |
| 24 578 3 | 26 1 567 | 9 268 2478 |
| 12 789 89 | 3 4 67 | 5 1268 278 |
|-------------------+-------------------+-------------------|
| 5 3 4 | 1 69 2 | 68 7 89 |
| 8 1 7 | 69 5 3 | 26 4 29 |
| 9 6 2 | 48 7 48 | 1 3 5 |
*-----------------------------------------------------------*
P.S. Not sure why the 1st two grids above were pasted in from my 'copy/paste' of the puzzle, but I'll leave them here in case there is something of value.