2
$\begingroup$

Take the following Killer Sudoku (from the app "Killer Sudoku" by Studio Goya LLC) I have been struggling with for the last few hours. "Penciled" numbers are my notes about which numbers are possible in the cells.

Killer Sudoku Puzzle

I cannot seem to find the next step. The app I am using says that R1c3 can only be a 5. However, I fail to see the reason. Anything I have tried still allows a 4 to be placed there. What is the (probably very obvious) thing that I am missing here?

For those not familiar with Killer Sudoku rules: Normal Sudoku rules apply. In addition, numbers in cages must sum to the small number in the top left corner of the cages. Numbers cannot be repeated in cages.

Improve this question
$\endgroup$
0

1 Answer 1

Reset to default
6
$\begingroup$

Assuming you are asking about R1C3,

If you look at the top-left 3x3 box, there is only one square where the 5 can go. You've already correctly ruled out 5 from the cages summing to 6 and 7.

Improve this answer
$\endgroup$
2
  • 3
    $\begingroup$ As I suspected, the answer was so obvious that I missed it. Thank you very much. $\endgroup$
    – jeyk
    Aug 16, 2021 at 15:55
  • 1
    $\begingroup$ Also, box 1 has a three-cell 6-cage, which you have correctly identified as a forced 1-2-3 triple. Since r3c1 is in the same box, and belongs to a three-cell 7-cage, you could have started the sudoku by putting a 4 in there. $\endgroup$
    – Bass
    Aug 16, 2021 at 20:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.