Usage Guide

Basic Gameplay

Objective

Fill a 9×9 grid so that every row, every column, and each of the nine 3×3 boxes contains all digits from 1 to 9 exactly once. No repetition allowed in any unit.

How to Play

• Place a number: Tap or click an empty cell, then tap a digit from the number pad at the bottom of the screen.
• Pencil notes (candidates): Toggle Pencil mode, then tap cells to write small candidate digits. Useful for tracking possibilities.
• Erase: Tap the Erase button to clear a cell's value (or pencil marks when in pencil mode).
• Hint: Tap Hint to reveal one correct cell's value.
• Undo: Tap Undo to reverse your last move (supports full undo history).

Difficulty Levels

Each difficulty level determines how many cells are pre-filled (given) at the start:

Level	Given Cells	Best For
Easy	45	Beginners & quick games
Medium	36	Casual players
Hard	31	Regular solvers
Expert	27	Experienced players
Master	24	Puzzle masters

Game Controls

iPhone / iPad

• Tap an empty cell to select it
• Tap a number on the keypad to place it
• Toggle Pencil mode to enter/erase candidate notes
• Use Erase to clear a cell
• Use Hint for help when stuck
• Use Undo to take back moves

Mac

• Left-click an empty cell to select it
• Type a number key (1–9) or click the on-screen keypad to place
• Toggle Pencil mode for candidate notes
• Keyboard shortcuts:
  • ⌘N — New game
  • ⌘Z — Undo
  • ⌘1 through ⌘5 — Start new game at each difficulty level

Smart Features

Pencil Notes System

When you enable Pencil mode, you can write small candidate digits in empty cells. The smart pencil system:

• Auto-clears peer pencil marks: When you place a definitive number, pencil marks for that digit are automatically removed from all cells in the same row, column, and box.
• Toggle per cell: Switch between entry mode and pencil mode at any time.

Error Checking

Optional error highlighting shows incorrect entries in red, helping you learn without spoiling the puzzle.

Daily Challenge

A fresh Master-level puzzle is generated every day. Your daily challenge progress is tracked in Statistics with a calendar view showing your streak.

Statistics

Track your Sudoku journey:

• Total games played and win rate
• Current streak and best streak
• Per-difficulty breakdown: games won, best time, average time
• Daily Challenge calendar with completion indicators

Themes

Choose from eight beautiful color themes in Settings:

Theme	Style
Classic	Clean white with blue accents
Midnight	Dark mode with deep blues
Paper	Warm parchment texture
Forest	Natural greens
Ocean	Calm sea blues
Sunset	Warm orange gradients
Lavender	Soft purple tones
Rose	Elegant pink palette

iCloud Sync

When signed into iCloud on your device:

• Game saves sync automatically — continue on any device
• Statistics and settings stay in sync
• Daily Challenge progress transfers across devices
• Requires iOS/iPadOS 16+ or macOS 15+

Game Center

Connect with Game Center to:

• Compete on leaderboards for best completion times per difficulty
• Earn achievements: First Solve, Easy/Medium/Hard/Expert/Master Clear, Flawless (no hints or errors)

Print Puzzles (Mac)

On Mac, print puzzles directly from the app:

1. Open the Print dialog from the toolbar
2. Select difficulty level (Easy through Master)
3. Toggle "Include Answers" if desired
4. Click Print

Perfect for solving offline with pen and paper!

Sound Effects

Sudoku includes subtle sound effects:

• Number placement confirmation
• Hint revealed
• Error alert
• Victory celebration

Toggle sound on or off in Settings → Sound.

Tips and Tricks

• Start with what's given — scan rows, columns, and boxes that already have many numbers filled.
• Use pencil notes — they're especially helpful on Hard, Expert, and Master difficulties.
• Look for naked singles — if a cell has only one possible candidate, fill it in.
• Look for hidden singles — if a digit can only go in one place within a row/column/box, place it there.
• Use hints sparingly — they're great for learning, but completing a puzzle without hints feels more rewarding.
• Build your daily streak — the Daily Challenge is a great way to practice consistently.