The New Sudoku Players' Forum

[NoClue]

Hi, all,

here is an EXTREMELY EASY (!!!) Sudoku - I tried to solve - it has got 31 clues: (# 649791 - very hard)

Code: Select all

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

I could hardly find ANY hidden singles (29 only) - so I had to pencilmark 21 cells.

Code: Select all

+--------+---------+---------+
|37. 37 8|2. 1. 5..|6.. 4. 9.|
|6.. 1. 5|47 9. 34.|78. 38 2.|
|4.. 9. 2|8. 37 6..|5.. 1. 37|
+--------+---------+---------+
|8.. 2. 3|49 6. 49.|1.. 7. 5.|
|5.. 6. 7|3. 8. 1..|2.. 9. 4.|
|1.. 4. 9|5. 2. 7..|3.. 6. 8.|
+--------+---------+---------+
|379 5. 4|1. 37 389|789 2. 6.|
|2.. 37 6|79 5. 389|4.. 38 1.|
|379 8. 1|6. 4. 2..|79. 5. 37|
+--------+---------+---------+

Any hints and tips are appreciated. Thanks in advance

[JeJ]

You keep mentioning in your posts naked and hidden singles but they are not the only techniques that can be used to solve a puzzle. There are some puzzles which their level of difficulty require more advanced techniques.

In your game, I see a skycrapper on r3c59 and r7c5 r9c9 that could eliminate "7" from r7c7, with that you get locked candidates to eliminate "7" from r9c1.
"9" can be eliminated from r7c6 because there are locked candidates again
Then you can eliminate 7 from r3c5 because there is a turbot fish (another technique you should learn) and from there the puzzle can be solved by singles.

[NoClue]

Hi JeJ,

many thanks for the hints and tips - the Skyscraper and the locked candidates cause big problems for me...