Always start with the region that has the most givens
Beginners often look at the whole board and do not know what to do first. A simpler approach is to find a row, column, or 3×3 block with only a few empty cells. List the missing digits and test each position against the other two intersecting regions.
After placing a digit, do not immediately jump to a distant area. Rescan the row, column, and block that changed because the new digit may reveal the next move. This habit creates a natural solving chain and reduces search time.
- Prioritize regions with only 1–3 empty cells.
- Find the missing digits before evaluating individual cells.
- Rescan the three related regions after every certain move.
Do not fill every cell with candidates too early
On Easy and Medium, most boards can be opened with direct scanning. If you write all 1–9 candidates into every cell from the start, you create much more information to read and maintain. Add notes only in stuck regions or cells with two or three possibilities.
When a candidate is eliminated, remove it immediately. Stale Notes are a common reason beginners think a puzzle is contradictory or requires guessing when the real problem is simply outdated candidates.
If you feel you must guess, switch regions first
A proper Sudoku can be solved with logic. When you see a cell with two possibilities and want to try one, stop and switch to another row, column, or block. Very often, a certain move elsewhere will come back and resolve that cell without an assumption.
Undo should correct input mistakes, not become a way to test answers. If you need Undo many times in one game, lower the difficulty by one level and practice region scanning and Pencil marks again.
- Do not stay stuck on one region for too long.
- Do not rely on a digit merely 'looking right'.
- Use hints to learn why a move works, not just to get the answer.
When should you move from Easy to Medium?
You do not need to chase a fixed time target yet. Increase the difficulty when you can finish several Easy games in a row with few mistakes and rarely need hints. The goal is to understand every move, not just finish the board.
At Medium, start learning hidden singles and locked candidates. These two techniques move you from “seeing the answer immediately” to reading candidate structure and prepare you for Hard Sudoku.
Apply it immediately on a real puzzle
A technique becomes automatic only after you use it across many different boards. Play at a manageable level, prioritize certain deductions, and review the step that caused you to get stuck.