Rows
A row runs left to right. Each row needs 1–9 with no repeated numbers.
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
Goal
Fill the grid so every row, column, and bold 3×3 box contains the numbers 1–9 exactly once.
Board Layout
A Sudoku board has 81 squares. The squares are organized into rows, columns, and 3×3 boxes.
Some squares already have numbers when the puzzle starts. Those are givens: they stay fixed, and you fill the empty squares.
Columns
A column runs top to bottom. Each column also needs 1–9.
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
3×3 Boxes
The bold lines split the board into nine smaller boxes.
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
Legal Moves
Before you place a number, check the empty square’s row, column, and 3×3 box.
- You can place any number 1–9 into an empty square.
- That number cannot already appear in the same row, column, or 3×3 box.
- Givens are fixed and cannot be changed.
Sudoku is a logic puzzle. You can solve it by checking what still fits.
Check the square
For this empty square, look across the row, down the column, and inside the 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
How You Win
The puzzle is solved when every row, column, and box is complete with no repeated numbers.
Pencil Marks
- Pencil marks are notes you add to remember possible numbers.
- They are not final answers and do not complete a square.
- You can remove pencil marks when the board proves that a number cannot belong there.
Sudoku Race Rules at FFG
- Sudoku Race uses the same classic Sudoku rules as solo play.
- Both players get the same puzzle, and the race starts only after both players are ready and the host starts it.
- The first correct completion wins the race.
- Before the race starts, the guest can leave the lobby and the host can kick the guest to reopen the seat.
- If a player gives up during a live race, the remaining active player wins.
FFG Difficulty Levels
- Easy: frequent sure numbers and gentle starts.
- Medium: more cross-checking and note cleanup.
- Hard: fewer obvious placements and more elimination patterns.
- Expert: deeper candidate work, chains, and harder endgames.
- Legendary: the most demanding puzzles FFG tracks.
Technique Terms
These are the solving patterns FFG tracks for Sudoku puzzles. The Sudoku Techniques Guide gives the full explanation and visual board example for each one.
Basic Techniques
- Naked Single
- A square has only one possible number left.
- Hidden Single
- A number has only one possible home inside a row, column, or box.
Intermediate Techniques
- Locked Candidate
- Candidates for one number inside a box all sit on the same row or column.
- Naked Pair
- Two cells in one row, column, or box contain the same two notes.
- Hidden Pair
- Two numbers can only go in the same two cells of a row, column, or box.
- Naked Triple
- Three cells in one row, column, or box share only three possible numbers.
Expert Techniques
- Naked Quad
- Four cells in a row, column, or box contain only four shared digits between them.
- Hidden Quad
- Four numbers can only go in the same four cells of a row, column, or box.
- Hidden Triple
- Three numbers can only go in the same three cells of a row, column, or box.
- X-Wing
- One number lines up in the same two columns across two rows, or the same two rows across two columns.
- Skyscraper
- Two two-choice lines for the same number point to a shared removal.
- Two-String Kite
- A two-choice row and a two-choice column connect through a box and force one removal.
- Simple Coloring
- Two colors mark a chain of one-or-the-other choices for one number.
- W-Wing
- Two matching two-note cells use a connecting one-or-the-other link to remove a shared note.
- XY-Wing
- One two-note pivot points to two wings that share a removable note.
- XYZ-Wing
- A three-note pivot and two wings remove a shared note from cells touching the whole pattern.
- Swordfish
- One number is locked across three rows and three columns.
- Jellyfish
- One number is locked across four rows and four columns.
- Finned X-Wing
- An almost X-Wing has one extra note that still allows a few removals.
- Finned Swordfish
- An almost Swordfish has an extra fin note that narrows where removals are allowed.
- Finned Jellyfish
- An almost Jellyfish has one or more extra fin notes that allow narrow removals.
Advanced Techniques
- Guess / Backtracking
- A controlled branch tries one possible number and backs out if it breaks the rules.
Want a shorter version? See How to Play.