Sudoku for beginners
Sudoku is a number puzzle that needs no maths at all — only careful looking. The grid has 9 rows, 9 columns and 9 boxes of 3×3 squares. Some numbers are already given. Your job is to fill every empty square so that each row, each column and each box contains the digits 1 to 9 exactly once. You can try every step below in Sudoku Tide, which has four difficulty levels, notes and hints.
1. Scan for the easy places
Pick a digit, say 5. Look at one box and ask: where can the 5 go in this box? Every 5 that is already in the same row or column “blocks” that row or column for this box. Often only one square is left — that is where the 5 must go. Go through the digits 1 to 9 like this, box by box. On easy puzzles, scanning alone solves most of the grid.
2. Look for the last number in a line
When a row, column or box has eight digits filled in, the ninth is obvious: it is the only digit missing. Fill these straight away — they often open up new places for scanning.
3. Use notes (pencil marks)
On harder puzzles, scanning stops working at some point. Then write small notes in the empty squares: all the digits that could still go there, given the row, column and box. In Sudoku Tide, switch on Notes and tap the small numbers. Notes turn the puzzle into a list of possibilities you can shrink step by step.
4. Single candidates
If a square has only one note left, that digit goes there. And if a digit appears in the notes of only one square within a row, column or box, it must go in that square too — even if that square has other notes. These two rules, the naked single and the hidden single, solve a large part of medium puzzles.
5. Pairs
If two squares in the same row (or column, or box) both have exactly the same two notes, for example 3 and 7, then those two squares will hold the 3 and the 7 between them. That means no other square in that row can be 3 or 7, so you can erase those notes elsewhere in the row. This simple “pairs” trick unlocks many harder puzzles.
6. Keep your notes up to date
Every time you place a digit, erase it from the notes in the same row, column and box. Out-of-date notes are the most common reason for getting stuck — or for making a mistake.
7. Don't guess
A well-made sudoku always has exactly one solution that can be found by logic. If you feel you must guess, it usually means there is a step you have not spotted yet: go back to scanning, check for singles, or look for pairs. When you are really stuck, a hint shows you the next step without spoiling the whole puzzle.
Choose your level
Start with the easiest level until scanning feels natural, then move up one level at a time. There is no rush: a sudoku is just as satisfying on a quiet evening as during a short break.
Play Sudoku Tide and try your first puzzle with these steps.
