dailysudoku.com

guest · Guest

hi,

I'm stuck on yesterdays sudoku.
I have only been able to find 2 numbers until now.

Guest · Guest

I found some help using Sudoku-San Wink

Steve R · Posted: Thu Feb 09, 2006 2:15 pm Post subject:

I generally take an age to spot this particular step.

It is to run through the candidates for r6c3. Only one is admissible.

Steve

Guest · Posted: Fri Feb 10, 2006 8:12 pm Post subject:

Have found r6c3 which then led to finding r5c5 ... but i have been staring at this for a couple of hours now ... and i cant see a way in ... any clues peeps?

David Bryant · Joined: 29 Jul 2005 Posts: 559 Location: Denver, Colorado

After you place the "2" at r6c3 you have
{3, 6, 7, 8} in column 7
{2, 4, 9} in row 6
"1" in middle right 3x3 box

The only possible value that can fit at r6c7 is therefore a "5".

Now look at row 5, and concentrate on the three cells in the middle of the row (r5c4, r5c5, & r5c6). You've already placed the "2" at r5c5, apparently. So there are only two cells left open there.

-- Since you now have a "5" in r4c2 and a "5" in r6c7 you can see that the "5" in row 5 must fit in one of these two boxes.

-- But you also have a "9" at r1c1 and another "9" at r6c8, so the "9" in row 5 will also have to fit in one of these two boxes.

-- Now you know that the pair {5, 9} must fit in r5c4 & r5c6 in some order. This leaves only one place for a "3" in the middle center 3x3 box. It also means that the pair {3, 4} must fit into the cells on either end of row 5 -- that is, at r5c1 & r5c9.

I hope that's enough to get you rolling. dcb

Guest · Posted: Fri Feb 10, 2006 10:58 pm Post subject:

ty david ... id have been staring at that for ages ... after your greatful reply i found where i had gone wrong ... id had an error in my pencil marks that have 53 as a possiblity for r6c7, which should not have been there due to the 3 @ r7c7 ... i can sleep again now Embarassed