THE PLAYBOOK · SZHLJS
How to play Classic Sudoku
The SZHLJS guide to Classic Sudoku starts with rules before speed. Your task is to fill all cells with 1–9; do not repeat a symbol in any row, column or region. The controls and example below describe this exact implementation.
Rules before speed
Work slowly for one round. Explain the rule behind each choice before trying to improve your score or completion time.
Your goal
Fill all cells with 1–9; do not repeat a symbol in any row, column or region.
Step by step
- Select an empty cell. The original clues cannot be edited.
- Choose a symbol from the number pad, or type it on a keyboard.
- Turn Notes on to record candidate symbols without committing an answer.
- Use Check entries to check your filled values. Hint reveals one value from the verified solution.
- 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 3 × 3 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
Which controls should I use?
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.
Can you show a concrete example?
Before filling a cell, compare the symbols already used in its row, column and 3 × 3 region. A candidate must be absent from all three.
What is included in this edition?
A real 9 × 9 puzzle with 3 × 3 regions, candidate notes, undo and saved progress. Every included puzzle is checked for a unique solution.
