The New Sudoku Players' Forum

[Amonra]

Got stuck on this:
.937612.4
....53..6
1........
.1....4.8
4.2...9.5
..8...67.
........7
6..82....
3.514.86.
Thanks much!

[Leren]

Code: Select all

*------------------------------------------------------------*
| 58   9       3    | 7      6     1      | 2    58      4   |
| 278 #2478    47   | 249    5     3      | 17   189     6   |
| 1    56-2478 467  | 249   *89   *2489   | 357  359-8   39  |
|-------------------+---------------------+------------------|
| 579  1       679  | 23569  379   2569-7 | 4    23      8   |
| 4    36-7    2    | 36     1378  68-7   | 9    13      5   |
| 59   35      8    | 23459  139   2459   | 6    7       123 |
|-------------------+---------------------+------------------|
| 289 #248     149  |*3569  *39    569    | 15-3 12459-3 7   |
| 6   #47      1479 | 8      2    *579    | 135  13459   139 |
| 3   #27      5    | 1      4    *79     | 8    6       29  |
*------------------------------------------------------------*

You don't say where you are stuck, so I've included all 4 non-trivial moves required to solve this puzzle.

After a basic mark-off there is a pointing pair of 8's in r3c56 that removes 8 from r3c28.

Next there is a pointing pair of 3's in r7c45 that removes 3 from r7c78.

Next there is a pointing pair of 7's in r89c6 that removes 7 from r45c6.

Lastly there is a naked quad (2478) in r2789c2 that removes 247 from r3c2 and 7 from r5c2.

You'll then find that 7 is a hidden single in Row 5, so r5c5 is 7.

This is the first of a whole cascade of singles that continues until the solution is complete.

For brevity I've included all four non-single moves in the diagram.

Leren

[Amonra]

It was the quad! I had the rest but did not recognize the quad. Thanks!