Sudoku Tips: 8 Techniques to Solve Faster

Whether you're new to Sudoku or stuck on the hard boards, these eight techniques — ordered from beginner to advanced — will speed up every solve. Remember: a proper Sudoku never needs guessing. Every digit can be deduced.

Beginner

1. Scan for a digit. Pick a number and look across rows, columns and boxes where it already sits. Those lines block it elsewhere — often leaving just one legal cell in a box.
2. Finish near-complete lines. A row, column or box with eight cells filled forces the ninth automatically.
3. Pencil in candidates. For tough cells, note every digit still legal there. When only one survives, it's forced (a "naked single").

Intermediate

1. Hidden singles. If a digit can only go in one cell of a row, column or box — even if that cell has other candidates — place it.
2. Naked pairs. If two cells in a line share the same two candidates, those digits are locked to that pair; remove them from the rest of the line.
3. Pointing pairs. If a digit in a box is confined to one row or column, eliminate that digit from the rest of that row or column outside the box.

Advanced

1. Hidden pairs. If two digits can only go in the same two cells of a line, those cells must hold them — clear any other candidates from those two cells.
2. X-Wing. When a digit's candidates in two rows line up in exactly the same two columns, you can eliminate that digit from those columns elsewhere. The first "big" pattern that cracks expert boards.

How to improve fastest

Drills beat theory. Start on easy to make scanning automatic, then climb to medium and hard. Our free unlimited Sudoku has three levels, mistake highlighting and a hint button, plus a daily challenge to keep a streak going.

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