Thursday, 5 October 2017

WSC Practice #5: Round 6 - Puzzle 9: Big Small Count Sudoku

This is the Fifth practice puzzle for the 2017 WSC.

I wasn't really sure how this variant was going to work. The example has a lot of givens, so I wasn't sure how it would work from that. I set up an opening section and figured I'd go from there. The opening section actually gave more information than I expected and I managed to reduce the second half of the puzzle a bit. It wouldn't get unique though, so I added an extra circle just to fix a small uniqueness issue. It doesn't make for the prettiest Sudoku, but it's a nice result anyway.
I generally like these kind of circle count puzzles, because it gives a fun interaction. Every time a circle gets figure out, a bit of new information gets revealed. It's like you're adding extra clues to the grid during the solving process.

Rules for Sudoku

In this Sudoku there are a number of circles. A digit in a circle indicate either "the number of neighbouring digits bigger than that digit" or "the number of neighbouring digits smaller than that digit" or both. Not all possible circles are marked.


  1. ...OK, this time, I'm *sure* you haven't already answered this question in the post. So are "neighboring" digits those whose squares share as little as a corner, or do they have to share an edge to count?

    1. Hi. Yes, the up-to-eight shared cells around the circles, touching by at least a corner. There was a legend in the WSC booklet clarifying the meaning of neighbouring.