Expert Sudoku – the ultimate challenge
Also requires hidden pairs or X-Wing. Every step can be solved logically.
Expert Sudoku – Maximum difficulty free online
Also requires hidden pairs or X-Wing. Every step can be solved logically.
Play Sudoku
Pick a difficulty, enter numbers with keyboard or touch, and print the current puzzle whenever you want.
ID 408917FB
Arrow keys: select cell · 1–9: digit · N: notes · Delete: erase · Ctrl/⌘ Z: undo
What makes expert Sudoku so demanding
Levels are based on the solving techniques required: naked singles, hidden singles, candidate eliminations, and finally hidden pairs or X-Wing. New puzzles are checked against these levels and can be solved without guessing.
Advanced techniques
At expert level you need techniques such as X-Wing, Swordfish and XY-Wing. Swordfish extends the X-Wing idea across three rows and columns. XY-Wing uses three linked cells with two candidates each to eliminate a number elsewhere. These patterns solve positions where simpler techniques fail.
Strategy and patience
Expert Sudoku rewards a calm, methodical approach. Never tackle a cell by guessing; a single wrong entry can make the whole puzzle unsolvable. Keep your candidates up to date and rely on the advanced patterns to solve even the toughest grid with pure logic.
Frequently asked questions
What is the best way to start as a beginner?
Start with an easy Sudoku. Focus first on rows, columns and 3x3 boxes that already contain many digits, because those usually reveal the next safe move fastest.
What should I do if I get stuck?
Move to another area of the grid and compare row, column and box again. It also helps to use notes for candidates instead of guessing.
How do the difficulty levels differ?
Levels are based on the solving techniques required: naked singles, hidden singles, candidate eliminations, and finally hidden pairs or X-Wing. New puzzles are checked against these levels and can be solved without guessing.