Learn Sudoku
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A visual guide · Sudoku

Learn Sudoku

Use logic to complete the grid — solo or in a live race.
9×9
grid · 81 cells
1–9
digits used once per unit
1–2
solo or live race
Section 01 · Setup

Start from the given clues.

Clue cells are fixed. Your job is to fill every empty cell without repeating a digit in its row, column, or 3×3 box.

5
3
7
6
1
9
5
9
8
6
8
6
3
4
8
3
1
7
2
6
6
2
8
4
1
9
5
8
7
9
Every row, column, and outlined 3×3 box must contain 1 through 9 exactly once.
Section 02 · Your move

Choose one empty cell and enter a digit.

A useful candidate must satisfy all three constraints at once: the row, the column, and the 3×3 box containing that cell.

Section 03 · Tactics

Look for units with only a few possibilities left.

Scan rows, columns, and boxes with many clues. When one digit has only one legal position, place it and rescan the intersecting units.

Section 04 · Turn flow

A turn, in order.

①
Scan the givens.
Find rows, columns, and boxes that are already close to complete.
②
Eliminate impossible digits.
Use existing numbers to narrow the candidates for each empty cell.
③
Place a forced value.
When only one digit can fit a cell or one position can hold a digit, enter it.
④
Repeat until the grid is complete.
Each correct placement creates new information for nearby cells.
Section 05 · Legal vs. illegal

What counts — and what does not.

Legal

Using each digit 1 through 9 once per row.
Using each digit 1 through 9 once per column.
Using each digit 1 through 9 once per 3×3 box.

Not allowed

Repeating a digit in a row, column, or box.
Changing one of the original clue cells.
In race mode, trying to inspect or edit the other player's board.
Section 06 · Winning

A correct completed grid finishes the puzzle.

Solo play ends when the board is correct. In a two-player race, both players solve the same puzzle separately and the first correct completion wins.

Section 07 · Try it

Now play a quick game.

Try a solo puzzle to learn the keypad, or create a room and race a friend while watching each other's completion progress.