I started solving sudokus regularly last summer and, little did I know then, I was jumping on a growing trend. Recently, I’ve been scouring the web for sudoku variations, two of which I had encountered in the US Puzzle Championship test. The best article I can find on the topic is one from the Mathematics Association of America which pretty much covers the range of sudoku variations I’ve seen. The article doesn’t have many sample puzzles below, so I’ll comment on the variations below and link to some puzzles you can try.
There are a few obvious ways to change a sudoku puzzle:
- Change the grid. Either change the size (e.g. the super sudoku found through this blog) or change the shape of the internal blocks (e.g. the jigsaw sudoku).
- Provide more information about which number goes in which square (e.g. the even-odd sudoku found on the World Sudoku Championship test or the greater-than sudoku). The advantage of these kinds of sudokus is that fewer numbers need to be filled in at the start, if any at all.
- Put something other than numbers in the individual squares. This can be a straight substitution of other symbols for the digits, like the hamster sudoku. The more ingenious variations mentioned in the MAA article include using digital clock numbers or dice pip numbers. The advantage in these cases is that entire numbers need not be taken away. You can take away inidvidual dice pips or sections of digital clock numbers. It’s another way to provide more limitted information.
The MAA article ends by suggesting some other possible variations that have not yet been devised, including a chess sudoku that would be very interesting.
