## Sudoku 676358 - very hard

Post the puzzle or solving technique that's causing you trouble and someone will help

### Sudoku 676358 - very hard

Hi, all,

that extremely easy puzzle I couldnÂ´t solve :

Code: Select all
`+-----+-----+-----+|4 . .|. 1 . |. . 8||. . 6|. . .|4 . 3||. 9 .|8 . 4|. . .|+-----+-----+-----+|. . 7|. . .|. . 6||8 . .|7 . 6|. . 5||9 . .|. . .|8 . .|+-----+-----+-----+|. . .|3 . 9|. 2 .||6 . 4|. . .|7 . .||3 . .|. 2 .|. . 4|+-----+-----+-----+`

This Sudoku has 26 given numbers

Too less hidden singles I found, as you can see as followed:

Code: Select all
`+-----------+----------------+-----------+|4.. 7. 235.|259.. 1... 235..|29.. 6.. 8.||125 8. 6...|259.. 7... 25...|4... 159 3.||125 9. 1235|8.... 6... 4....|12.. 157 27|+-----------+----------------+-----------+|125 34 7...|12459 3589 12358|1239 149 6.||8.. 34 12..|7.... 39.. 6....|1239 149 5.||9.. 6. 125.|1245. 35.. 1235.|8... 147 27|+-----------+----------------+-----------+|7.. 5. 8...|3.... 4... 9....|6... 2.. 1.||6.. 2. 4...|15... 58.. 158..|7... 3.. 9.||3.. 1. 9...|6.... 2... 7....|5... 8.. 4.|+-----------+----------------+-----------+`

I only found 21 hidden singles, so I had to pencilmark 34 (!!!) cells.

Any help is appreciated.
NoClue

Posts: 48
Joined: 01 April 2011

### Re: Sudoku 676358 - very hard

First, you missed these basic moves. However, the remaining solution is not trivial.

Code: Select all
`         Hidden Single                   =  3    r1c6,r3c3         Hidden Single                   =  3    r6c5         Naked  Single                   =  9    r5c5   c1b1  Locked Candidate 1              <> 1    r4c1`
daj95376
2014 Supporter

Posts: 2624
Joined: 15 May 2006

### Re: Sudoku 676358 - very hard

Hi, daj95376,

I canÂ´t explain and understand, how you found the hidden singles in r1c6, r3c3 and r6c5. Locked candidate 1 is it equal to "Pointing Pairs"?

Greetings
No Clue
NoClue

Posts: 48
Joined: 01 April 2011

### Re: Sudoku 676358 - very hard

Hidden Single = 3 at r1c6 and r3c3 come from having put 6 at r3c5 which you had already done.

3 at r3c3 leaves "3" as a hidden single at r6c5 which in turn leaves 9 as a naked single at r5c5
JeJ

Posts: 76
Joined: 06 January 2011

### Re: Sudoku 676358 - very hard

Hi, JeJ,

I didnÂ´t understand the messages you wrote about the hidden singles. I couldnÂ´t spot any hidden singles more than the ones I could find out in the 2nd version of the Sudoku (the sudoku with the pencilmarks)

NoClue

Posts: 48
Joined: 01 April 2011

### Re: Sudoku 676358 - very hard

Sorry sometimes explaining it is not so easy.

Go back to your candidates, check box 2. "3" is a hidden single on r1c6.

Check row 3, "3" is a hidden single on r3c3.

Those two placements, leave "3" as a hidden single at r6c5 which in turn leaves 9 as a naked single at r5c5
JeJ

Posts: 76
Joined: 06 January 2011

### Re: Sudoku 676358 - very hard

Hi, JeJ,

yesterday I checked my Sudoku again - the hidden singles in r1c6 and r3c3 I found with your help.

Thanks
NoClue

Posts: 48
Joined: 01 April 2011