This blog post may have been changed since its original publication during a blog migration.

Click here to solve this puzzle online. Link no longer works :(

Rules:

Classic Sudoku rules. In addition, consecutive numbers on the Indiana border cannot add up to 9 (i.e., 9, 1+8, 1+2+6).

Background:

I made this puzzle as the summer of 2021 came to a close on August 13. I was thinking about going back to college in Indiana and I wanted to make a puzzle about it. I already made one puzzle with the Purdue logo so I wanted to try incorporating the state into the puzzle. Initially, I tried to use Indiana's highway system as the lines to form a Slitherlink but it became very tedious to trace over these maps accurately. Then I came up with the idea to superimpose the border of the state on a sudoku after playing a German Whispers Sudoku with Germany superimposed on the grid. The puzzle was found in the WPF 2020 Newsletter. The additional constraint was created so the border could have some relevance to the puzzle. I believe I landed on that specific constraint because I was doing some Kakuro around the same time and had the sums to 9 still rattling in my head. In hindsight, the constraint is difficult to explain and I would probably replace it with another one but I'm still satisfied with the puzzle overall.