The New Sudoku Players' Forum

[NoClue]

Hi, all,

I tried to solve this VERY EXTREMELY EASY (!!!) Sudoku. It has 30 clues, has the number 650025 and its difficulty is: very hard

Code: Select all

+-----+-----+-----+
|. 5 .|. . 6|4 7 .|
|8 . .|. 3 4|. . .|
|. . 7|. . .|. . 3|
+-----+-----+-----+
|3 9 .|6 . 7|. . .|
|. . 4|3 . 5|8 . .|
|. . .|8 . 1|. 3 4|
+-----+-----+-----+
4 . .|. . .|9 . .|
|. . .|9 6 .|. . 5|
|. 8 6|4 . .|. 2 .|
+-----+-----+-----+

I could hardly find ANY hidden singles (only 34) - so I had to pencilmark 17 cells.

Code: Select all

+-------+-----+-----------+
|1. 5. 3|2 8 6|4... 7. 9..|
|8. 26 9|7 3 4|1256 15 126|
|26 4. 7|5 1 9|26.. 8. 3..|
+-------+-----+-----------+
|3. 9. 8|6 4 7|125. 15 12.|
|67 1. 4|3 2 5|8... 9. 67.|
|5. 67 2|8 9 1|67.. 3. 4..|
+-------+-----+-----------+
|4. 3. 5|1 7 2|9... 6. 8..|
|27 27 1|9 6 8|3... 4. 5..|
|9. 8. 6|4 5 3|17.. 2. 17.|
+-------+-----+-----------+

Any tips and hints will be appreciated. Thanks in advance

[JeJ]

Again you'll need more advanced techniques than singles to solve this one.

There is a Unique Rectangle Type 3 on 1 and 5 on r24c78 by which you can eliminate "1" from r24c7 which leaves a single on c7r9 that cracks the puzzle.

[docjohn]

(my first post so forgive me if the format doesn't work)

You can also solve it with with a Skyscraper

+-------------------------------+-------------------------------+-------------------------------+
| 1 5 3 | 2 8 6 | 4 7 9 |
| 8 26 9 | 7 3 4 | 1256 15 126 |
| 26 4 7 | 5 1 9 | 26 8 3 |
+-------------------------------+-------------------------------+-------------------------------+
| 3 9 8 | 6 4 7 | 125 15 12 |
| 67 1 4 | 3 2 5 | 8 9 67 |
| 5 67 2 | 8 9 1 | 67 3 4 |
+-------------------------------+-------------------------------+-------------------------------+
| 4 3 5 | 1 7 2 | 9 6 8 |
| 27 27 1 | 9 6 8 | 3 4 5 |
| 9 8 6 | 4 5 3 | 17 2 17 |
+-------------------------------+-------------------------------+-------------------------------+

look for the 6's in rows 35 cols 79
r2c9<>6
r6c7<>6

the rest is naked and hidden singles

[Leren]

There is a finned XWing in 6's r26c27 with a fin at r2c9 => r3c7 <> 6. That should do the trick.