Let Sudoku notes make the grid quieter.
Use candidate notes to simplify Sudoku decisions without filling every empty cell with possibilities.
Candidate notes are most useful when they reduce uncertainty. If every empty cell is filled with tiny numbers, the puzzle can feel busier instead of clearer.
Use Sudoku notes to record candidates.
A candidate is a digit that could still fit a cell based on its row, column, and box. Notes are a way to keep those possibilities visible while you continue solving.
You do not need to record every possible digit immediately.
Start with cells that have fewer candidates.
Look for cells that have only two or three reasonable candidates. Those notes are easier to compare and more likely to become useful after another number is placed nearby.
A cell with six candidates usually does not need your attention yet.
Update candidate notes after a confirmed move.
When you place a number, check the row, column, and box it touches. Remove that digit from candidate notes in those units.
This small habit prevents old possibilities from staying on the board after they are no longer valid.
Look for a naked single or hidden single.
Notes are not only reminders. They help reveal changes. A cell with candidates 2 and 7 becomes solved when 7 is ruled out. A row where only one cell still contains candidate 4 tells you where 4 belongs.
The value of notes is in what disappears.
For example, suppose a cell has candidates 2 and 7. If a confirmed 7 appears elsewhere in its column, remove 7 from that cell’s notes. The remaining 2 is a naked single. A hidden single is different: one digit has only one possible cell within a row, column, or box.
Keep scanning alongside your notes.
Before filling candidates across the whole grid, scan for direct placements. Check the fullest units. Follow one digit through neighboring boxes.
Many puzzles can be simplified before detailed notes are needed.
Keep useful notes, without chasing perfection.
You do not have to maintain a flawless notation system. If a section becomes obvious, solve it and move on. The goal is to make the next deduction easier, not to create a complete map of every possibility.
Add notes when they make the next move clearer.
If you can explain a move without writing anything down, make the move. If two or three possibilities keep competing for your attention, add the notes.
That is enough.
Can two cells with the same notes form a pair?
Yes, when two cells in the same row, column, or box each have exactly the same two candidates. Those digits must occupy those two cells, so you can remove them from other cells in that unit. Two cells that merely share one candidate do not establish a pair.
Try it on a fresh grid.
Start with a puzzle that gives you room to practise candidate notes without feeling rushed.
Play Sudoku →