dailysudoku.com

xMetaRidley · Joined: 30 Sep 2006 Posts: 2

I am pretty new to sudoku, and have been stuck on this one for a while. When I asked for the hint, it gave me this. Any ideas of the logic behind it?

keith · Posted: Sat Sep 30, 2006 9:37 pm Post subject: Naked triple

Look in the last three cells of Row 9. They contain a triple <368>; 3 cells, 3 possibilities.

So, you can clear these possibilities from the other cells in the row (and in Box 9). In particular, R9C5 is not <68>, it must be <2>.

I think the rest of the puzzle is routine.

Keith

xMetaRidley · Joined: 30 Sep 2006 Posts: 2

I see, thanks

ravel · Joined: 21 Apr 2006 Posts: 536

What you dont need:
1 in row 2 can only be in box 3 => r1c79<>1, r3c79<>1 => r2c8=1
(which would have been my hint)
or:
5 in box 1 can only be in row 3 => r3c9<>5
5 in box 9 can only be in row 7 => r7c123<>5
1 in column 7 can only be in box 1 => r2c8<>1, r123c9<>1
8 in row 8 can only be in box 7 => r79c13<>8

(Keith already told you) What you need:
Hidden triple 479 in r9c134 => r9c1<>368,r9c34<>28