Expert sudoku
A fresh puzzle each time. Your progress is saved on this device.
Paused. The timer has stopped.
Expert puzzles are the hardest we publish. They suit experienced players who are at home with Hard grids and want something to really get stuck into. Expect to slow down, look carefully, and enjoy the payoff when the key move appears.
Which techniques you need
Expert puzzles on sudoku.ie may need everything from the lower levels, plus:
- XY-wing: three two-candidate cells linked in a bent chain.
- XYZ-wing: a close relative where the middle cell has three candidates.
- Swordfish: the X-wing stretched to three rows and three columns.
Every Expert puzzle still has exactly one solution and can be solved by reasoning. You never need to guess.
How long it takes
Most players take 30 minutes or more. An hour is not unusual, especially when you are learning the techniques.
When to play
Saturday’s daily puzzle is always Expert. It makes a good weekend project.
A tip
Expert puzzles often stall after a good start. When that happens, work through the techniques in order, simplest first. If nothing turns up, look for cells with exactly two candidates. They are the building blocks of the XY-wing, and finding one usually breaks the grid open. Then pick a single digit and scan the whole grid for an X-wing or swordfish.