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How to Play Sudoku: Four Moves That Solve Almost Any Board
Written by Lin ยท Updated 2026-10-22 ยท 2 min read
Sudoku has one rule and a hundred ways to panic about it. The rule: fill the grid so every row, every column and every 3x3 box holds the digits 1 through 9 once. There is no arithmetic, no guessing, and no reward for being fast, which is why it stays relaxing even when it gets hard.
Beginners stall because they look for the answer instead of the constraint. These four habits fix that. Everything below you can practice on a small 6x6 board first, then carry to a full grid.
Steps
- 1
Start where the numbers already are
Pick a digit that already appears several times and ask where the last copies can go. If a 7 is blocked in two rows of a box, the third row is the only place it can sit. This is the single most common way a cell gets solved.
- 2
Scan the empty corner of a box
Look for a 3x3 box with only one or two empty cells. Check what digits its row and column already hold, and the leftover cell almost always has one answer left.
- 3
Use the row and column together
When a cell could be two digits, scan its row and its column. If one of the two already appears in either line, the other is the answer. You never guess, you only rule out.
- 4
When you are stuck, change your target
Do not hammer the same box. Switch to a different digit and scan the whole grid for it once more, or move to a row that is almost full. A finished cell somewhere else usually unlocks the one you were stuck on.
What a box, a row and a column mean
The grid is nine rows, nine columns and nine boxes, and a digit must be unique in all three at once. That double bookkeeping is the whole puzzle: a cell is allowed a number only if that number is absent from its row, its column and its box together.
How to start instead of staring
Do not scan cell by cell, scan by digit. Pick the number that is missing from the fewest places and walk it through the board, asking where it cannot be. Wherever a digit can only go in one cell of a box, that cell is solved.
When to bring out pencil marks
On a real 9x9 you will eventually have a cell that could be two or three digits. Lightly write those candidates in the corner. When another solved cell deletes one of them, the last survivor is your answer. The mark is a memory aid, not a guess.
If you want a smaller grid to learn on
Sudoku Mini uses a 6x6 grid with the same rules, so you can see all four techniques before a full board overwhelms you. If you enjoy the scanning, Nonogram and Hanoi scratch the same logic itch with a different shape.
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