🧩 What is Sudoku? A Complete Beginner's Guide

New to Sudoku? This guide explains everything you need to know — from how the puzzle is structured to the logic used in solving it. Start your puzzle-solving journey here.

🧠 The Basic Concept

Sudoku is a logic-based number placement puzzle played on a 9x9 grid, divided into nine 3x3 subgrids (called boxes or regions). The objective is simple: fill the entire grid so that each row, column, and 3x3 box contains the digits 1 through 9 exactly once.

📐 Puzzle Structure

• Rows: 9 horizontal lines, each must contain 1–9 without repetition.
• Columns: 9 vertical lines, also containing 1–9 uniquely.
• Boxes: 9 square regions of 3x3 cells, must also contain 1–9.

The puzzle starts with some cells pre-filled — these are known as clues. The number of clues determines the puzzle’s difficulty.

📏 Rules Recap

• Every row must contain the numbers 1–9 exactly once.
• Every column must contain the numbers 1–9 exactly once.
• Every 3x3 box must contain the numbers 1–9 exactly once.

🚀 Why Play Sudoku?

Sudoku is more than just a time-killer. It’s a brain exercise that improves concentration, logical thinking, and patience. It’s also incredibly satisfying to solve, especially as difficulty increases!

🎯 Sudoku at Sudoku99

Sudoku99 offers puzzles from Level 1 (36 clues) to Level 20 (17 clues) — a highly structured progression that lets you improve step-by-step. You can play online, print puzzles, and even track your scores.

🧩 Try a Beginner Puzzle

👉 What's Next?

• Learn Basic Solving Techniques →
• Explore Difficulty Levels →
• Browse Sudoku Practice Books →