Sudoku Néon
The Sudoku classic in retro neon: fill the 9×9 grid with digits, no repeats, as fast as you can. 3 levels.
Read the rules below, then start your run.
About this game
Sudoku Néon is the most famous logic puzzle of them all, dressed in a polished retro-neon skin and built to play with a mouse or a finger. The rule is universal and horribly addictive: a grid of nine cells by nine, cut into nine boxes of three by three, into which you place the digits 1 to 9. The golden rule is simple to state and brutal to master: every row, every column and every 3×3 box has to hold all nine digits exactly once, with no repeats. The grid starts with a handful of clues — digits given and locked — and from those, by pure logical deduction, you slowly fill the empty cells. No luck, no blind guessing: every Sudoku Néon grid has a single solution, guaranteed at generation, reachable entirely by reasoning. To help you think, the game offers modern, discreet aids: a notes mode for pencilling candidates into a cell, automatic highlighting of conflicts when a digit appears twice in a row, column or box, and highlighting of every cell carrying the same digit as the one you have selected. Play at your own pace or against the clock: your score is your solving time, so the faster you fill the grid, the better your record (the shortest clock wins). The timer starts on your first digit and stops dead when the grid is complete; note that every wrong digit adds a five-second penalty, rewarding care without ever costing you the game. Three difficulty levels suit your mood and your experience: Easy, ideal for learning and unwinding with a well-filled grid; Medium, for a proper logic challenge; and Hard, with few clues, reserved for seasoned solvers going for the top of the leaderboard. Play on a keyboard at your desk — digits 1 to 9, arrow keys to move from cell to cell, Delete to fix — or with a finger on mobile, thanks to a large touch number pad under the grid, in the thumb zone, with clear notes and erase buttons. The neon look is built for instant readability: the given digits stand clearly apart from the ones you enter, the 3×3 separators are thick and bright, and every mistake or completed line gets a measured visual and audio cue, smooth at 60 frames per second. Sudoku Néon is free and instant in your browser, nothing to install. Create an account to sync your best times, enter the leaderboard for each level and unlock trophies such as solving a grid without a single error. Can you crack the Hard Sudoku clean?
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How to play
Fill the 9×9 grid with the digits 1 to 9 so that every row, every column and every 3×3 box holds each of them exactly once.
Game rules
- The grid arrives with clues already placed and locked: those cannot be changed.
- Pick an empty cell, then enter the digit from 1 to 9 that logic tells you belongs there.
- Every row, every column and every 3×3 box has to hold all nine digits with no repeats.
- Use notes mode to pencil the possible candidates into a cell before you commit.
- Lean on the conflict highlighting and the matching-digit highlighting to spot your mistakes.
- The solution is unique and reachable by pure deduction: no cell ever has to be guessed.
Controls (keyboard and touch)
- Digits 1-9Place a digit in the selected cell
- Arrow keysMove the selection around the grid
- DeleteClear the selected cell
- Number pad + notes button (touch)Enter a digit, switch to notes mode or erase
How a run ends
You win by filling the whole grid correctly. Your score is your solving time — the shorter the better — and every wrong digit adds a five-second penalty.
Tips & strategy
Hunt the constrained cells
Look for rows, columns or boxes where only one spot is left for a given digit. Those certain placements usually set off a chain reaction of further deductions.
Pencil before you commit
On ambiguous cells, note every candidate. Eliminating candidates as you go is far more reliable than dropping a digit in and correcting it later.
Mistakes are expensive
The clock only starts on your first digit, and each error costs you five seconds. Take a second to check before you confirm rather than playing fast and paying for it.
Did you know?
Modern Sudoku started life as "Number Place" in the United States in 1979, before being popularised in Japan through the 1980s by the publisher Nikoli, which gave it the name we use today. "Sudoku" roughly means "single digit".
Contrary to a common belief, Sudoku involves no arithmetic at all: it is pure logic and deduction, and the digits could be replaced by symbols. Its worldwide wave came from daily newspaper publication starting in 2004, which turned it into a ritual for millions.
Frequently asked questions
- Is Sudoku Néon free to play?
- Yes. Sudoku Néon is completely free and runs straight in your browser — no download, no install, no paywall.
- How do you play Sudoku Néon?
- Hit “Play” to start Sudoku Néon. It runs on keyboard on desktop and on touch controls on phones and tablets — no controller needed.
- Do I need an account to play?
- No — you can play right away as a guest, and your best score is kept on this device. A free account (by email link, no password) syncs your high scores, puts you on the leaderboards and unlocks trophies.
- Does Sudoku Néon work on mobile?
- Yes. The game is responsive and fully playable with your fingers on phones and tablets, just like on desktop, with no app to install.
- Can a Sudoku grid have more than one solution?
- Not here. Every grid we serve has a single solution, reachable by deduction alone. If you are torn between two digits for a cell, it means a deduction is waiting somewhere else — not that the grid is ambiguous.
- What is notes mode actually for?
- It lets you pencil small candidates into a cell without committing them as an answer. It is your scratch pad for testing possibilities, ruling out the impossible and locking in your deductions before you write the final digit.