Killer Sudoku

THE PLAYBOOK · CDBRM

How to play Killer Sudoku

For Killer Sudoku, CDBRM puts the actual rules alongside the playable board or activity. Fill rows, columns and boxes with 1–9 once. Cage digits cannot repeat and must add to their clue. The suggested practice focus is mistake-aware practice.

8 finite checked puzzles, with local saved progress. No claim of unlimited daily puzzles or calibrated difficulty.

Mistake-aware practice

Read the common mistake below before starting. Watch for that situation during the round rather than relying on trial and error.

Your goal

Fill rows, columns and boxes with 1–9 once. Cage digits cannot repeat and must add to their clue.

Step by step

1. Select an editable cell.
2. Enter a value using the keypad or keyboard; Notes stores candidates.
3. Read the region, cage, arrow or outside clues alongside the normal constraints.
4. Check entries verifies the completed board; Undo reverses your last input.
5. New puzzle selects another included puzzle.

Controls

Click or tap cells and the digit pad. Use Notes, Undo and Reveal selected. Large boards scroll inside the game.

A useful example

A two-cell cage labelled 3 holds 1 and 2; a one-cell cage fixes its own value.

Watch out for this

A full board must obey every extra rule. Reveal supplies assistance; it is not an earned deduction.

Common questions