How to Play Sudoku
Sudoku is one of the world's most popular logic puzzles. Whether you're a complete beginner or looking to sharpen your skills, this guide covers everything you need to know — from the basic rules to advanced solving strategies.
What is Sudoku?
Sudoku is a logic-based number-placement puzzle. The objective is to fill a 9×9 grid so that each column, each row, and each of the nine 3×3 sub-grids (called "boxes") contain all of the digits from 1 to 9 exactly once. No math is required — just pure logical deduction.
How do I play Sudoku?
Start by looking for rows, columns, or boxes that are nearly complete. Identify which numbers are missing and use elimination to determine where each number must go. Tap or click a cell, then select a number. If you get stuck, use the Notes feature to pencil in candidates.
What are the rules of Sudoku?
There are three simple rules: (1) Each row must contain the numbers 1–9 with no repeats. (2) Each column must contain the numbers 1–9 with no repeats. (3) Each 3×3 box must contain the numbers 1–9 with no repeats. A valid Sudoku puzzle has exactly one solution.
What are the best Sudoku strategies for beginners?
Start with Naked Singles — cells where only one number is possible. Then try Hidden Singles — numbers that can only go in one place within a row, column, or box. Use pencil marks (notes) to track candidates. Scanning rows and columns systematically helps you spot placements faster.
Is Sudoku good for your brain?
Yes! Research suggests that puzzles like Sudoku can help improve concentration, logical thinking, and short-term memory. Regular puzzle-solving may help keep the mind sharp and is often recommended as a cognitive exercise for all ages.
What difficulty levels does Sudoku.ie offer?
Sudoku.ie offers four difficulty levels: Easy, Medium, Hard, and Expert. Easy puzzles have more given numbers and can be solved with basic techniques. Expert puzzles require advanced strategies like X-Wing, Swordfish, and chain deductions. There is also a Daily Challenge that changes every day.
Ready to play?
Put your skills to the test with a free puzzle. Choose your difficulty and start solving.