How to Play Sudoku — Beginner's Guide

Sudoku is the world's classic logic puzzle: a deceptively simple grid that can keep you thinking for hours. If you are just getting started, this article will help you understand the rules and start solving today.

The Basic Rules

A standard Sudoku grid is 9×9 cells, divided into nine 3×3 boxes. The game's single goal:

• Each row must contain the digits 1 through 9, each exactly once.
• Each column must contain the digits 1 through 9, each exactly once.
• Each 3×3 box must contain the digits 1 through 9, each exactly once.

The grid starts with some cells already filled. From there, you must reason out the rest. A proper Sudoku puzzle has exactly one solution — no guessing is needed; every step can be logically deduced.

Pencil-mark (Notes) Mode

When you are not sure what a cell contains, turn on notes mode and write the candidate numbers small inside the cell. This habit is essential: it lets you "calculate with your eyes" and spot cells that have only one remaining possibility.

The First Two Techniques to Learn

1. Naked single

If, after eliminating, a cell has exactly one possible candidate, that is the answer. This is the most basic deduction in Sudoku.

2. Hidden single

A digit appears exactly once among the pencil notes of a row, a column, or a box — it must go in that cell, even if the cell still lists other candidates.

Each time you place a number, go back and re-check the cells around it — every related cell loses candidates immediately.

Playing Sudoku on SynerWorlds

Our Sudoku has everything a beginner needs:

• 12 difficulty levels: from grids with about 45 givens (very easy to get into) down to grids with only about 22 (a real challenge).
• A 3-mistake limit per game — strict enough to make you think, but not punishing.
• A built-in pencil-mark mode plus hints — each hint names the technique it uses, so you learn while you play.
• A daily puzzle with a fresh grid every day, and race rooms where 2–4 players solve the same grid to see who finishes first.

Tips for Beginners

Start with the fullest rows, columns, or boxes — the more givens, the easier the elimination.

Scan one digit at a time across the whole grid: look for all the 1s everywhere before moving on to the 2s.

Write pencil notes for the hard cells early; don't try to carry it all in your head.

Never guess — if you feel like guessing, go back and check which elimination technique you missed.

You can play Sudoku right here — start at level 1 and get familiar with the reasoning as you play. Good luck with your first 9×9 grid!