## still helpless...:-(

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

### still helpless...:-(

Hi, all,

Here is a 28-clue Sudoku, # 648959 - which I couldnÂ´t solve at all: (difficulty: very hard)

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

With this Sudoku I could hardly find ANY hidden singles (only 31), so I had to pencilmark 22 cells!

Code: Select all
`+---------+----------+-------+|6. 9. 1..|24. 47. 3.|27 8. 5||58 4. 28.|1.. 57. 6.|27 9. 3||7. 35 238|258 9.. 28|6. 1. 4|+---------+----------+-------+|3. 1. 9..|6.. 2.. 4.|5. 7. 8||4. 8. 5..|3.. 1.. 7.|9. 2. 6||2. 6. 7..|9.. 8.. 5.|4. 3. 1|+---------+----------+-------+|1. 7. 4..|28. 6.. 28|3. 5. 9||58 2. 368|45. 345 9.|1. 46 7||9. 35 36.|7.. 345 1.|8. 46 2|+---------+----------+-------+`

I need a lot of tips and hints, how I can go on further...thanks in advance!
NoClue

Posts: 48
Joined: 01 April 2011

NoClue wrote:Here is a 28-clue Sudoku,
# 648959 (difficulty: very hard)

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

after 31 "singles" --

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

finned X-wing
to exclude 5 at r8c1
the 5 for columns 2,4
is in rows 3,8
except ("fin") r9c2

Pat

Posts: 3652
Joined: 18 July 2005