The basics

Cells are named like a spreadsheet. Columns are lettered A through I, left to right. Rows are numbered 1 through 9, top to bottom. So B5 is column B, row 5. Boxes are numbered 1 through 9, left to right, top to bottom.

Pick a cell, then pick a number. Turn on Notes to pencil in small candidate numbers instead. Your game saves automatically in this browser, so you can close the page and come back.

Mouse or touch

Click or tap a cell, then click or tap a number on the number pad.

Keyboard only

• Tab into the board. The board is one stop; Tab again moves on to the tools.
• Arrow keys move between cells. Home and End jump to the start or end of the row. Ctrl + Home / End jump to A1 (top left) or I9 (bottom right).
• 1–9 fill the cell. Shift + a number adds or removes a note.
• Backspace, Delete, or 0 clears the cell.
• N notes on/off. H hint. U or Ctrl/Cmd + Z undo. Shift + Ctrl/Cmd + Z redo.
• R, C, or B reads out the current row, column, or box and what's missing from it.
• Single-letter keys only work while you're in the board, so they never fire by accident elsewhere.

Mac Voice Control

• Every button has a visible name you can say: “Click Undo,” “Click Notes,” “Click Hint,” “Click 7.”
• Cells are named by position and what's in them, like “B5 blank” or “B5 7.” Say “Click B5 blank.” Turn on Show cell names on the board in Settings to see the names, or say “Show numbers.”
• Fastest way: say “Click Move” once, then dictate a whole move like “B5 7” or “note B5 3,” then say “Press Return.” Your cursor stays in the Move box, so just keep dictating moves. Spoken forms like “bee five seven” also work.

Windows Voice Access

• Say “Click Undo,” “Click Hint,” “Click 7,” and so on. Say “Show numbers” to label every cell.
• The Move box works the same way: “Click Move,” dictate “B5 7,” then “Press Enter.”

Screen readers

• The board is a grid. Each cell announces its name, its number or “blank,” and whether it's given, incorrect, or has notes.
• NVDA and JAWS switch to focus mode in the board automatically. If number keys jump to headings instead, press NVDA + Space or Insert + Z.
• Every move is confirmed out loud, for example “B5 set to 7.” Press R, C, or B to hear a row, column, or box.
• The Move box also takes “read row 3,” “read column E,” and “read box 3.”

Move box commands

• B5 7 — put 7 in column B, row 5. Also “set B5 to 7” or “column B row 5 7.”
• 7 — put 7 in the selected cell.
• note B5 3 4 — add or remove notes 3 and 4 in B5.
• clear B5 — empty B5.
• go B5 — select B5.
• read row 3, read column E, read box 3
• hint, undo, redo, notes on, notes off, pause, resume