Sudoku Arena

About Sudoku Arena

Sudoku Arena is a browser sudoku game built around a hundred graded puzzles rather than an endless stream of random grids. Levels 1–25 are easy, 26–50 medium, 51–75 hard and 76–100 very hard, split into ten named chapters that unlock one at a time. Each level keeps your best time, so the grid you cleared in eleven minutes in your first week is still there to beat.

Every puzzle is generated fresh and then checked by a solver before you ever see it, so each one has exactly one solution and can be reached by reasoning alone. There is never a point where the only way forward is to guess and backtrack. Difficulty is set by how much of the grid is given away — an easy level starts with forty-two numbers on the board, a very hard one with twenty-five — and by how deep the technique has to go before the next cell falls out.

You get three lives per puzzle. Put a number in the wrong square and you lose one; lose all three and the level ends and you start it again. It is a small change to ordinary sudoku and it changes how the game feels: filling a cell you are only fairly sure about now costs something, so the game rewards actually finishing the deduction instead of trying a digit to see what happens.

The number pad counts down as you go — each digit shows how many of it are still missing from the grid — and Notes mode puts pencil marks in a cell the way you would on paper. Arrow keys move the selection, 1 to 9 fill it, N flips notes on and off.

The Live Arena is the part that is not ordinary sudoku. Everyone in the room gets the same grid at the same moment, and a live board shows how many cells each player has correctly filled while they are still solving. It runs for ten minutes. Because the score is cells on a grid, it cannot climb past eighty-one, which makes it the rare online leaderboard where a wildly inflated score is not even arithmetically possible.

There is also a daily puzzle — the same grid for every player in the world, generated from the date, one attempt — with a streak that counts consecutive days, and eleven badges for things like clearing a hard level without losing a life or ten levels in a row with a clean sheet.

How to play Sudoku Arena

Press Level 1, or open the full grid of 100 and pick any level you have unlocked.

Click or tap an empty cell to select it, then press 1–9 to fill it.

Press N for Notes mode when you want to write pencil marks instead of answers.

Fill every cell correctly before you lose three lives. Beating a level unlocks the next one.

Open Live Arena to race the same grid against everyone else in the room, or Daily Puzzle for the one grid the whole world gets today.