Beginner's Guide: How to Play Sudoku

What Is Sudoku?

Sudoku is a puzzle where you fill a 9x9 grid so each row, column, and 3x3 box contains all digits from 1 to 9 exactly once. It's purely logic — no arithmetic required. Starting with some prefilled numbers (givens), you use elimination and pattern recognition to complete the grid.

Sudoku develops logical thinking, concentration, and problem-solving skills. Accessible yet challenging, it appeals to learners of all ages.

Benefits of Sudoku

Enhances Cognitive Skills: Boosts memory, attention to detail, and analytical thinking.
Reduces Stress: Focused puzzles offer a meditative break from daily worries.
Accessible Anywhere: Requires only paper and pencil—or a phone app—making it easy to practice.
Progress Tracking: Structured difficulty levels let you measure improvement over time.

Sudoku Grid & Basic Rules

The 9x9 grid is divided into nine 3x3 boxes. Rules to follow:

Each row must contain digits 1-9 without repetition.
Each column must contain digits 1-9 without repetition.
Each 3x3 box must contain digits 1-9 without repetition.

Never guess—use logic to deduce each placement. If stuck, revisit pencil marks and basic techniques before moving to advanced tactics.

Difficulty Levels

Puzzles are categorized by complexity: Easy, Medium, Hard, Expert. Beginners should start with Easy to master fundamentals:

Easy: Many givens, basic singles solve most cells.
Medium: Requires pairs and pointing techniques.
Hard: Involves X-Wing, Swordfish, and chaining patterns.
Expert: Demands advanced techniques like XYZ-Wing, ALS, and forcing chains.

Terminology & Notation

Cell: Individual square in grid.
Givens: Pre-filled numbers.
Candidate: Potential digit in an empty cell.
Pencil Mark: Small notation of candidates.
House: Any row, column, or box.

Solving Mindset & Workflow

Adopt a systematic approach:

Initial Scan: Fill “naked singles” and “hidden singles” across all houses.
Pencil Marks: Enter all candidates for remaining cells.
Basic Elimination: Use naked pairs and pointing techniques.
Advanced Patterns: Apply X-Wing, Swordfish, etc., if stuck.
Validation: Ensure each placement follows rules; backtrack if you meet a contradiction.

Consistent practice of this workflow builds confidence and efficiency.

Core Techniques

Naked Single

A cell with only one candidate—fill it immediately.

Hidden Single

A digit appears only once as a candidate in a house; that cell must be it.

Naked Pair/Triple

Two or three cells share identical candidate sets of size two or three—eliminate from others.

Pointing Pair/Triple

Candidates confined to one row/column within a box remove that candidate from the same row/column outside the box.

Intermediate & Advanced Techniques

X-Wing

Identify two rows (or columns) where a candidate appears exactly in the same two columns (rows)—eliminate that candidate from those columns in other rows.

Swordfish

Extension of X-Wing across three rows and columns.

XY-Wing

Three cells forming an XY pivot to eliminate candidates in overlapping houses.

Step-by-Step Walkthrough

Perform initial scan: fill all naked/hidden singles.
Populate pencil marks for remaining cells.
Apply pointing and naked pairs to reduce candidates.
When stalled, search for X-Wing or XY-Wing patterns.
Validate completed grid respects all rules.

Working through a sample puzzle following these steps cements your understanding.