The trick of making Sudoku games

The MathWithBadDrawings blog looks at how complicated — or, rather simple — it is to create lots and lots of sudoku games:

“Now, I’m not much of a Sudoku player. (Crossword guy, to be honest.) But glancing at the puzzle, my dad and I got to wondering: How do they generate these puzzles? We weren’t sure. So we found a more tractable question: What if you were a lazy Sudoku maker?…”

“Well, let’s start with this: the numbers don’t actually matter. For example, you could switch the 1’s and the 2’s. Nothing really changes. Every row still has a 1 and a 2. So does every column. So does every medium square. The symbols in Sudoku are meaningless. It doesn’t matter what they are—numbers, letters, emoji. It just matters where they are….”