How to play Sudoku Mates

Nine digits, three checks

Fill the empty cells of the 9×9 grid with digits 1–9. Every row, every column and every outlined 3×3 box must contain each digit exactly once. The starting clues are fixed; you cannot erase or replace them.

Start with a row, column or box that already has several clues. List the missing digits, then check the crossing row, column and box for each empty cell. A digit belongs in a cell only when all three checks allow it.

For example, a row containing 1 2 3 · 4 5 6 · 7 8 _ is missing 9. Before entering it, check that the cell's column and 3×3 box also permit 9. The aim is a complete correct board, rather than filling every space as quickly as possible.

Use the board and number pad

1. Select an editable cell, then choose a digit on the number pad. If you enable digit-first input in Settings, choose the digit first and then select its cell.
2. Switch on the pencil to record possible digits as small notes in an empty cell. Choose a noted digit again to remove that candidate. Notes are private and do not count as answers.
3. Use Erase to remove your editable digit. In Practice, it can also clear the notes in a selected empty cell. Where Undo is available, it restores the previous edit; it does not refund a counted mistake.

Highlighting can help you follow the selected row, column, box or digit. Available assists depend on the mode and, in a race, the host's rules. The in-game tutorial lets you try selecting a cell, entering a digit and using the pencil.

Practice: your own pace

Choose Solo practice for a private puzzle. Pick Easy, Medium, Hard, Expert or Master, and decide whether to show mistakes before starting.

In the browser, an incorrect digit stays on your board and increases the mistake count. Turning mistake highlighting off hides the visual warning, not the count. Correct or erase the entry to continue. Use Pause when you want to stop the Practice timer; resume when you are ready to solve again.

Practice progress and notes are saved on this device. They are separate from server race results and are not restored by signing in on another device.

Daily: one browser attempt each UTC day

The web Daily screen publishes the day's difficulty and mistake-highlighting setting. Everyone plays under those conditions, with an independently generated board. Each player profile gets one attempt per UTC date.

Connect to your profile, review the conditions and select Start daily puzzle. The server saves the board and result. The timer continues while you are away, so leaving the page does not pause this challenge. If a move is awaiting confirmation, use the offered retry to recover it.

Other players' Daily results stay hidden until you complete your own board. After finishing, you can compare times and mistake counts and refresh the results as more players finish. Pencil notes remain on this device. Browser Daily needs a connection; the mobile app's local Daily mode works differently.

Races: the same puzzle with friends

1. Create a room and choose its difficulty and rules, including the available notes, highlighting, free hints and mistake limit.
2. Share the invitation link or room code. A room holds 2–6 players. Joining a room does not automatically add anyone as a friend.
3. Get ready in the lobby. The host can start with at least two connected, ready players. The shared countdown leads everyone into the same puzzle on the same timer.

You fill your own board. Other players see your completion and mistakes, not your digits or notes. With your consent, cell sharing briefly reveals filled positions only. Spectators can watch progress without seeing private answers.

The first correct completed board wins. You can also win as the last player who has not been eliminated. Reaching the room's mistake limit loses the race, although you can keep solving; Undo does not reverse elimination or change a declared winner. When late joining is allowed, joining an ongoing race keeps its original timer.

Races need a network connection. If you disconnect, reconnect to recover the server-confirmed board and timer. See connection help before clearing any browser data.

Keep your profile, keep your privacy

Nobody mode needs no registered account. Its device credential reconnects your server profile, rooms and statistics. Losing that credential can prevent recovery.

You can optionally save a profile using an offered Google, Apple or email sign-in link. If that sign-in already has a profile, the app lets you use the existing profile or explicitly confirm a merge. Signing in does not transfer local Practice progress or pencil notes.

For data handling, export and deletion, read the Privacy Policy and deletion instructions. If something does not work as described, contact support without sending session credentials or sign-in links.