What is a Shidoku? The 4×4 Sudoku Variant

A shidoku is a sudoku variant where instead of a 9×9 grid divided into 9 regions, you have a much smaller 4×4 grid that’s divided into 4 regions. 

The term comes from ‘shi’ meaning ‘four’ in Japanese. 

The same basic rules of sudoku apply, however, instead of using the numbers 1 through 9, you simply only need the numbers 1 through 4. Below is an example of a completed shidoku grid. 

As you can see, the number sudoku rules of the same number only appearing once per column, row, and region also apply to shidukos. 

Because of their size, shidukos are much simpler and quicker to solve than regular sudokus. 

This has resulted in them being popular with children as a means of an introduction to the logic and rules of regular sudoku and are sometimes referred to as “children’s sudokus”. 

Play shidoku

Want to play some shidokus? Here are some for you to solve.