Rows
Each horizontal row must contain digits 1 through 9 exactly once. Start by identifying which digits are missing, then reject positions using their columns and boxes.
How to play Sudoku in Voku
Sudoku is a logic puzzle, not an arithmetic test. Fill every empty cell with a digit from 1 to 9 while respecting three constraints. A valid Voku puzzle begins with fixed clues, has exactly one verified solution, and never requires two copies of a digit in the same row, column, or 3×3 box.
The three rules work together
Columns
Each vertical column follows the same rule. A candidate that looks valid from the row can still be blocked by a matching digit higher or lower in its column.
3×3 boxes
The nine thick-bordered boxes also contain digits 1 through 9 exactly once. Every placement must satisfy its row, column, and box at the same time.
Your first solving loop
- 1Scan the most complete unit. List the digits missing from a row, column, or box.
- 2For each empty cell, remove digits already present in its other two units.
- 3Place a digit only when one candidate remains or one digit has only one possible position in the unit.
- 4After placing it, rescan the affected row, column, and box. New opportunities often appear immediately.
Notes
Toggle Notes before entering candidates. Voku stores multiple small digits in a cell and removes related notes when you confirm a value. Notes are possibilities, not guesses or final answers.
Hints
A hint reveals the correct value of one empty cell. Each game currently offers up to three; using one is recorded in your local result. Treat it as a way to resume learning, then inspect why the revealed value fits.
Undo
Undo restores prior board and manual-note states. It does not erase the record of a mistake or return a consumed hint, so results remain meaningful after correcting an input.
When you get stuck
Do not place a digit because it “looks likely.” Verify your notes, choose one missing digit, and scan every box for its legal positions. If basic scans are exhausted, continue with locked candidates or pairs. You can pause manually without adding paused time to the timer.
Open the technique path