Instructions

The objective is to fill the 9x9 grid with digits so that each of the nine rows, nine columns, and nine boxes (3x3 subgrids) contains all of the digits 1 through 9 exactly once.

A cell in the grid is selected or deselected by tapping on it.

A digit is entered or cleared in a selected cell by toggling the associated key of the keypad. The pencil key can be used to annotate one or more candidates.

Additional features and customizable settings are accessible from the menu.

Settings

Highlight

Digits
Highlight cells set to the selected digit.
Notes
Highlight the selected digit in notes.
Conflicts
Highlight cells in conflict with the selected digit.
Errors
Highlight all errors.

Notes

Compute on New
Automatically compute notes in new grids.
Auto-Clear
When a digit is entered, clear it from notes in the associated row, column, and box.
Sticky Note Key
Stay in note mode when selecting an empty cell.
Preserve on Clear
Do not erase notes on deselecting a cell's note key.
Promote on Clear
Promote single note to a digit on deselecting the note key.
Double-Tap Promote
Double tap a single note to promote it to digit.

Display

Timer
Show the timer.
Key Dots
In each key, show which boxes the digit is set in.
Bold Digits
Draw digits with a bold font.
Landscape Invert
Swap the grid and keypad in landscape orientation.
Full Screen
Show the grid and keypad in full screen.

Control

Grid Hovering
Allow moving around the grid when selecting a cell.
Number then Cell
Select a key while no cell is selected to toggle digit in subsequently tapped cells.

Theme

Aqua
Classic
Khaki
Retro
Night