Sudoku

Probably the most famous of all the Japanese-style logic puzzles, Sudoku (aka Su-Doku and Su Doku) sparked a mid-2000s craze that resulted in it becoming an established part of the lives of millions of people globally. Presented with a 9×9 grid containing starter numbers, the solver’s challenge is to place a number in each empty square so that each row, each column and each 3×3 block contains all the numbers from 1 to 9. The fewer starter numbers there are, the harder the challenge, and in this way, difficulty levels can be achieved from simple to fiendish.

The basic premise of sudoku can be adapted to many shapes and forms, so that there’s a version suited to every type and age of solver. For younger children, we can make a sudoku more accessible by reducing the grid size or giving more starter numbers. The numbers themselves can be replaced by fun symbols or pictures, such as with our digital Colour Sudoku. Symbols and pictures can be themed to suit a client or audience. Alpha Sudoku uses letters in place of numbers.

We can increase grid size up to the giant 16×16 Sudoku, and even overlap multiple grids such as with Samurai Sudoku which has five 9×9 grids arranged in the form of an X.

For a fresh challenge, there are variants of sudoku that take the basic puzzle and add an extra rule. Sandwich Sudoku has numbers at the end of each row and column to indicate the sum of the numbers that appear between the 1 and the 9 in that row or column. X-Factor Sudoku highlights the two main diagonals through the grid, each of which must also contain the numbers 1 to 9. 

Sudoku can be used as a competition puzzle, with the prize answer being the number or symbol which appears in a particular square of the completed puzzle. Alternatively, a code can be employed to create a spell-out, which adds an extra level of engagement.