Sudoku Variants Worth Checking Out

There’s so much more to Sudoku than just classic Sudoku with the regular 9×9 grid where you simply add the numbers 1 to 9 in each row, column, and 3×3 subregion. 

That’s not to say there’s anything wrong or bad with classic Sudoku—it’s one of the most popular games of logic there is! But why constrain yourself to just vanilla Sudoku? 

Here is a list of Sudoku variants that are well worth checking out. 

Grid size variations

Perhaps the most common type of Sudoku variation involves different size Sudoku grids. 

More commonly known as Latin Squares, you can have any sized square (3×3, 5×5, 16×16, etc.) and have the rule that every row and column must contain the numbers 1 through to the size length of the square. So with a 5×5 sized grid, each row and column would have to include the numbers 1 to 5 exactly once. 

Technically, the distinction between regular Sudoku and a 9×9 Latin Square is the addition constraint where the numbers 1 to 9 must also appear in all 9 3×3 subregions. 

This additional subregion constraint can also appear in certain sized Sudoku variants such as the 4×4 Shidoku and the 16×16 Hexadoku. 

These subregions can also appear with grid sizes where it’s not as easy to divide the number of squares into uniform subregions. Such as with the 5×5 Godoku ​​where the grid is divided into 5 irregular 5-cell subregions. 

And, of course, there’s also Samurai Sudoku that overlaps 5 different Sudoku grids that all need to be solved!

Other types of Sudoku variants

In addition to differently sized Sudoku grids, there are plenty of other types of Sudoku puzzles that involve additional constraints and/or provide different types of clues.

The most simple form of these Sudoku types is diagonal Sudoku where there’s an additional requirement that each of the two 9-cell diagonals must contain the numbers 1 to 9 each once.

More advanced and irregular Sudoku variations include:

  • Arrow Sudoku
    • Where ‘arrows’ are overlaid on the grid and the numbers along the arrow shaft must sum to the number at end.
  • Chess Sudoku
    • Where additional constraints prevent the same digit from appear a ‘knight’s move’ or a ‘King’s move’ away from each other.
  • Killer Sudoku
    • Where additional regions are overlaid on the grid and the squares within these regions must sum to a given value.
  • Kropki Sudoku
    • Where black and white dots are placed between certain cells to indicate that they must either be consecutive or have a ratio of 1:2. 
  • Renban Sudoku
    • Where lines are added over a number of squares along which the squares must contain a set of distinct consecutive digits.
  • Sandwich Sudoku
    • Where numbers are placed outside the grid as additional clues that tell you how many digits are ‘sandwiched’ between the 1 and 9. 
  • Skyscraper Sudoku
    • A 3D take on Sudoku where the digit of a square corresponds to its ‘height’. 
  • Thermo Sudoku
    • Where a number of ‘thermometers’ are overlaid on the grid and where the numbers placed in cells containing a thermometer must increase in value from the bulb end to the top.

Ready to play these Sudoku variants online?

If any of these Sudoku variations sound interesting to you, click on the links above to learn more about them!