Alphabet Sudoku.
Learn the rules, see the possibilities.
Alphabet Sudoku replaces numbers with letters while keeping the same placement logic. On a 9×9 board, use A–I so that each row, column, and 3×3 box contains every letter exactly once. You do not need to spell words: letters act as symbols, just as digits do in Classic Sudoku.
How to play Alphabet Sudoku
Three ideas. Illustrated on the board. Take them one move at a time.
Complete a row of letters
Compare the letters in a row with the full symbol set displayed on the keypad. On a 9×9 board the set is A, B, C, D, E, F, G, H, and I. If a row has all but one of these letters, the missing letter is forced. The highlighted row shows a completed example.
Think of letters as nine different tokens. Their positions do not need to form a word.
Check the vertical letter set
Before entering a letter, look down the entire column. A letter that is missing from the row may already appear in its column, which rules it out for that cell. Combining horizontal and vertical checks prevents the most common beginner mistakes.
Use the on-screen letter keypad or type the letter directly on your keyboard.
Finish the box, not a hidden word
Each thick-bordered box needs one copy of every allowed letter. Use the letters already present in that box, then check the crossing row and column of an empty cell. On other board sizes the symbol set changes: A–D for 4×4, A–F for 6×6, and A–P for 16×16.
On larger alphabet boards, H and N are letter inputs. Use the toolbar buttons for hints and notes.
Sudoku strategies that work in every variant
Every Sudoku is solved with the same three habits. They need no arithmetic and no guessing — just a careful look at what each cell can still be.
Scan rows, columns, and boxes
Pick a number and sweep the grid. Where a number already appears, it cannot go again in that row, column, or box. Three placed copies often leave only one open cell for the fourth.
Hunt for singles
Look for a cell with just one possible symbol left. A row or box that is almost complete is the fastest place to find one, and each single you place narrows the next cell.
Write candidates, then eliminate
When two or three cells stay open, switch on Notes and pencil in the possibilities. Cross out candidates as peers fill in. If a digit fits only one cell inside a group, that cell must hold it.
A few Alphabet Sudoku facts
The 9×9 symbol set
Nine letters stand in for nine digits.
Words you need to spell
Alphabet Sudoku is a placement puzzle, not a word search.
The 16×16 symbol set
Larger boards need sixteen distinct letters.
Symbol sets depend on your chosen grid size.
Make yourself at home on the board.
Choose a cell, enter a symbol, and keep going. Use Notes for possibilities, Undo to revisit a move, and Hint when you need a nudge. Change the visual theme without changing your game.
- ↑↓←→
- Move between cells
- A–P
- Enter an allowed letter
- Del
- Erase your entry
- Ctrl / ⌘Z
- Undo the last move
Alphabet Sudoku, explained.
A few things you might be wondering.
Is Alphabet Sudoku different from number Sudoku?
The symbols differ, but the core row, column, and box rules are the same. Replacing every letter consistently with a digit produces an equivalent placement puzzle.
Do the letters have to spell a word?
No. The goal is to use each allowed letter exactly once in every row, column, and box. Alphabet order and word meaning do not impose extra rules.
Which letters are used on a small board?
A 4×4 board uses A–D and a 6×6 board uses A–F. A 9×9 board uses A–I, while a 16×16 board uses A–P.