Arkadium’s Sudoku

Arkadium’s Sudoku is the standard puzzle with nothing bolted on. The board is the familiar 9×9 grid, split into nine 3×3 squares, and the goal is the one every sudoku player knows: fill each row, each column and each square with the numbers 1 to 9, with no number repeated in any of them.

Input works in two steps. You click a number first and then click the empty box where it should go, which keeps the board clean and makes it easy to place the same digit several times in a row while you are working through one number at a time. The pitch is simply that you no longer need a pen or a pencil.

Arkadium has been publishing classic puzzle games for years, and this is its take on sudoku in the browser: a single grid, logic only, solved when the last box is filled. It is a sensible first stop if you want plain sudoku rather than a variant with extra rules.

1. Look for a row, column or 3x3 square that is nearly complete.
2. Click the number that is missing from it.
3. Click the empty box where that number belongs.
4. Keep going until every box is filled with no repeats.

Work one digit at a time. Because you pick the number before the box, it is quickest to place every 5 you can find, then every 6, and so on.