Hard Sudoku

How to solve Hard Sudoku

What makes a puzzle Hard is the hardest step it needs. Most often that step is Pointing Pair (60%), Naked Pair (18%), Box/Line Reduction (13%), or Hidden Pair (6%).

Hard is where notes start to pay. Pencil in the candidates, then look for a number whose candidates in one box all sit in a single row or column: that number can then be removed from the rest of that row or column. Pairs and triples of candidates work in a similar way.

Learn Pointing Pair step by step →

Hard Sudoku: questions and answers

How many numbers do Hard puzzles start with?

Every Hard puzzle here starts with 31 of the 81 squares filled in.

Do Hard puzzles need guessing?

No. Every puzzle has exactly one solution, and the hint engine of our app solves each one with logic alone, one technique at a time.

Can I get a hint while I play?

Yes. Hint names the technique the next step needs and shows it on your board one step at a time, with the same hint engine our app uses.

What comes after Hard?

One level up, Expert puzzles are most often decided by Skyscraper.

All six levels

• Easy SudokuNearly Complete (95%)
• Medium SudokuHidden Single (100%)
• Hard SudokuPointing Pair (60%), Naked Pair (18%), Box/Line Reduction (13%), or Hidden Pair (6%)
• Expert SudokuSkyscraper (55%), Y-Wing (30%), or Empty Rectangle (6%)
• Master SudokuXY-Chain (59%), W-Wing (28%), X-Chain (6%), or XYZ-Wing (5%)
• Extreme SudokuALS-XZ (86%) or Unique Rectangle (12%)

More Sudoku to play

• Print Hard Sudoku
• Daily Sudoku: four new puzzles every day
• Sudoku checker
• Sudoku for kids