## Stuck! Please walk me through this one. "Evil"

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

### Stuck! Please walk me through this one. "Evil"

from websudoku.com : Evil

. . 8 | . . 1 | 4 . 7
. 1 . | 6 . . | . . .
9 . . | . . . | . . 3
_____________________
. . 2 | . 5 . | . . .
. 5 . | 1 6 7 | . 2 .
. . . | . 4 . | 7 . .
_____________________
8 . . | . . . | . . 2
. . . | . . 2 | . 3 .
3 . 6 | 8 . . | 5 . .

http://www.websudoku.com/?level=4&set_id=8063445051

I'm not sure if it's worth putting my progress because I was unable to get very far. What technique do I need to use?

thanks
lagvoid

Posts: 6
Joined: 12 December 2006

Lagvoid,

Actually, it would be useful to see your progress.

The hardest techniques I used to solve it were locked candidates and a naked triple. Here is your original grid and the pencilmark grid after filling in a few singles. Look at the 8's in box 5.

Code: Select all
` *-----------* |..8|..1|4.7| |.1.|6..|...| |9..|...|..3| |---+---+---| |..2|.5.|...| |.5.|167|.2.| |...|.4.|7..| |---+---+---| |8..|...|..2| |...|..2|.3.| |3.6|8..|5..| *-----------* *--------------------------------------------------------------------* | 256    36     8      | 359    239    1      | 4      569    7      | | 257    1      3457   | 6      23789  34589  | 289    589    589    | | 9      467    457    | 457    278    458    | 1268   1568   3      | |----------------------+----------------------+----------------------| | 167    36789  2      | 39     5      389    | 13689  14689  14689  | | 4      5      39     | 1      6      7      | 389    2      89     | | 16     3689   139    | 2      4      389    | 7      15689  15689  | |----------------------+----------------------+----------------------| | 8      479    14579  | 34579  1379   6      | 19     1479   2      | | 157    479    14579  | 4579   179    2      | 1689   3      14689  | | 3      2      6      | 8      179    49     | 5      1479   149    | *--------------------------------------------------------------------*`
re'born

Posts: 551
Joined: 31 May 2007

This was where I got stuck. Thank you for taking the time to look at this puzzle.

Code: Select all
` *--------------------------------------------------------------------* | 256    36     8      | 39     29     1      | 4      569    7      | | 257    1      3457   | 6      2789   3459   | 29     589    59     | | 9      467    457    | 47     278    45     | 126    1568   3      | |----------------------+----------------------+----------------------| | 167    36789  2      | 39     5      389    | 1369   1469   1469   | | 4      5      39     | 1      6      7      | 389    2      89     | | 16     3689   139    | 2      4      389    | 7      1569   1569   | |----------------------+----------------------+----------------------| | 8      479    1479   | 5      3      6      | 19     1479   2      | | 157    479    14579  | 47     179    2      | 68     3      68     | | 3      2      6      | 8      179    49     | 5      1479   149    | *--------------------------------------------------------------------*`
lagvoid

Posts: 6
Joined: 12 December 2006

rep'nA wrote:Actually, it would be useful to see your progress.

rep'nA, it was a phish.
wapati
2010 Supporter

Posts: 527
Joined: 13 September 2006

lagvoid wrote:This was where I got stuck. Thank you for taking the time to look at this puzzle.

Code: Select all
` *--------------------------------------------------------------------* | 256    36     8      | 39     29     1      | 4      569    7      | | 257    1      3457   | 6      2789   3459   | 29     589    59     | | 9      467    457    | 47     278    45     | 126    1568   3      | |----------------------+----------------------+----------------------| | 167    36789  2      | 39     5      389    | 1369   1469   1469   | | 4      5      39     | 1      6      7      | 389    2      89     | | 16     3689   139    | 2      4      389    | 7      1569   1569   | |----------------------+----------------------+----------------------| | 8      479    1479   | 5      3      6      | 19     1479   2      | | 157    479    14579  | 47     179    2      | 68     3      68     | | 3      2      6      | 8      179    49     | 5      1479   149    | *--------------------------------------------------------------------*`

lagvoid, you've made a mistake in assuming r7c4=5... In box 8 both r7c4 and r8c4 can be 5, and you cannot make the decision yet...

Anyway, the key move for this puzzle is a naked triple of {457} on r3, which will crack the grid into singles...

wapati, what was a "phish"?
udosuk

Posts: 2698
Joined: 17 July 2005

Thanks for the quick replies. I can't wait to take a look at this. I'll find the time one of these days and I'll be sure to reply here with an update!
lagvoid

Posts: 6
Joined: 12 December 2006

Ah, "naked triple" worked! Thanks again for the help. I overlooked these before. Relief...
lagvoid

Posts: 6
Joined: 12 December 2006