4x4 Sudoku

THE PLAYBOOK · CDBRM

How to play 4x4 Sudoku

Use CDBRM to play 4x4 Sudoku and read its instructions on the same page. Fill all cells with 1–4; do not repeat a symbol in any row, column or region. Follow the learn from a completed round approach for your next round.

Learn from a completed round

Finish a round where possible, then identify one decision you would change. Revisit the example or mistake section for a focused second attempt.

Your goal

Fill all cells with 1–4; do not repeat a symbol in any row, column or region.

Step by step

1. Select an empty cell. The original clues cannot be edited.
2. Choose a symbol from the number pad, or type it on a keyboard.
3. Turn Notes on to record candidate symbols without committing an answer.
4. Use Check entries to check your filled values. Hint reveals one value from the verified solution.
5. Complete the board, or choose New puzzle for another board.

Controls

Tap or click a cell and use the number pad. Keyboard: arrows select cells; digits (and A–G on 16×16) enter values; Backspace erases.

A useful example

Before filling a cell, compare the symbols already used in its row, column and 2 × 2 region. A candidate must be absent from all three.

Watch out for this

Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.

Common questions