The basics

Sudoku for beginners

Most beginners get stuck for the same reasons. This plan avoids them and gets you to Medium puzzles quickly.

Step 1: know the rule

Each row, column and 3 by 3 box needs the digits 1 to 9 once. If you are unsure, read how to play Sudoku and the rules first.

Step 2: master two single techniques

Most of an Easy puzzle falls to two ideas. A hidden single is a digit that has only one place left in a row, column or box. A naked single is a cell that has only one digit left. Practice both on Easy puzzles until they are automatic.

Step 3: scan in a pattern

Random looking leads to missed moves. Scan one digit at a time (all the 1s, then all the 2s and so on), then scan rows, columns and boxes with the most digits. A steady routine finds more moves than inspiration does.

Step 4: start using notes

When singles run out, write the possible digits in each empty cell. Notes turn invisible patterns into visible ones. See notes and pencil marks for a clean method.

Step 5: add pairs

Medium puzzles need naked pairs and pointing pairs. They only eliminate candidates, but each elimination often unlocks a new single.

Mistakes to avoid

• Guessing. It feels fast, but one wrong guess hides the real mistake.
• Skipping notes on harder puzzles. You cannot see eliminations in your head.
• Moving up a level too soon. Wait until Easy takes you under about ten minutes without hints.
• Not updating notes. After placing a digit, remove it from the notes of its row, column and box.

A practice order

1. Five Easy puzzles, no notes.
2. Five Easy puzzles, with notes.
3. Five Medium puzzles, using the solver in step mode only when stuck.
4. Then read how to solve Sudoku for the bigger picture.