Learn Sudoku Step-by-Step

Introduce Sudoku as a logic-based number puzzle

Explain how the 9×9 grid is made of rows, columns, and boxes

The fundamental rules of Sudoku

Define a 3×3 box and its importance in Sudoku

What makes a puzzle easy or hard

First steps when approaching a new Sudoku

When and how to use hints effectively

Using pencil marks to track possibilities

The simplest solving situation

When a cell can only contain one number

When a digit can only go in one place

When candidates in a box point along a line

When candidates in a line are locked to one box

Two cells with the same two candidates

Two digits that can only go in two cells

Three cells sharing three candidates

Three digits limited to three cells

Four cells sharing four candidates

Four digits limited to four cells

A powerful pattern based on two rows and two columns

Extension of X-Wing to three rows and columns

The ultimate fish pattern with four rows and columns

A pattern using three bi-value cells

Extended version of XY-Wing

Chains of bi-value cells for eliminations

Using colors to track candidate chains

Avoiding patterns that would create multiple solutions

A turbot fish pattern for eliminations

A turbot fish using one row and one column

Systematic guessing as a last resort