Learn Sudoku

Every technique the PuzzleCraft Hint Assistant uses, explained in plain English. Start at the top and work down: each one unlocks harder puzzles.

New to Sudoku? Read how to play first.

• EasyNaked SingleA square where only one number is still possible.
• EasyHidden SingleA number that has only one possible home in a row, column or box.
• MediumNaked PairTwo squares in a unit that share the same two candidates.
• MediumHidden PairTwo numbers that can only go in the same two squares of a unit.
• MediumPointing PairA box's candidates for a number all line up in one row or column.
• HardNaked TripleThree squares in a unit that only hold three numbers between them.
• HardHidden TripleThree numbers that can only go in the same three squares of a unit.
• HardBox/Line ReductionA row or column's candidates for a number all fall inside one box.
• ExpertX-WingTwo rows where a number can only go in the same two columns.
• ExpertXY-WingThree two-candidate squares that force a number out of their shared neighbours.