Box Brain Sudoku
Today's puzzle
Classic sudoku
Every row, column and 3×3 box holds 1 to 9 once each.
00:00
Tap a cell, then a digit. Turn on Notes for pencil marks. Keyboard: arrows, 1–9, N for notes.
One puzzle a day in each mode Come back tomorrow for a new one, or get unlimited puzzles, hints and streaks in the app.
Stuck? The app's hints don't just reveal a digit: they point to where to look, name the technique, then show the move.
The sudoku everyone knows: a 9×9 grid, some digits given, and one way to fill the rest. Every other mode here builds on these rules.
All 12 modes
- Every row, column and 3×3 box holds 1 to 9 once each.
- Classic rules, plus: the digits in each dashed cage add up to its total, with no repeats in a cage.
- Rows and columns hold 1 to 9 once, and so does each thick-edged shape.
- Classic rules, plus: digits get bigger along each thermometer, from the bulb to the tip.
- Classic rules, plus: the digits along an arrow add up to the digit in its circle.
- Classic rules, plus: a number outside the grid is the sum of the digits between the 1 and the 9 in that row or column.
- Classic rules, plus: a white dot joins consecutive digits, a black dot joins a digit and its double. No dot means neither.
- Classic rules, plus: each sign points at the smaller of its two cells.
- Classic rules, plus: both long diagonals hold 1 to 9 once each.
- Classic rules, plus: the four shaded 3×3 areas hold 1 to 9 once each.
- Classic rules, plus: two cells a chess knight's move apart can't hold the same digit.
- Classic rules, plus: shaded squares hold even digits, circled cells hold odd digits.