Zdoku

Zdoku is Sudoku the way it should be: free, quiet, and out of your way. No ads interrupting a solve. Nothing to buy. No account unless you want one. Three ways to play Zen — no scoring, no timer pressure, no account. Just a puzzle and as long as you like to finish it. Pause whenever you want. Leaderboard — the clock is running and your time is ranked against everyone else's. Four difficulties, each with its own board. Multiplayer — up to four players race on the same puzzle in real time. Every player has a colour, correct cells lock in as they are found, and you can see the board fill up as it happens. Create a room and share the code, or join a public one. Built for actually playing • Four difficulties: Easy, Medium, Hard and Expert • Pencil notes, including marking several cells in a box at once • Realtime feedback in Zen, or turn it off and check at the end • Twelve themes, from bamboo forest to jellyfish to a night sky • Three background music tracks, or none at all • Your finished games are kept so you can look back at them No account needed Play as a guest and never sign up. If you want a name on the leaderboard, an account takes a username and a password — an email is optional, and only used if you forget that password. You can delete your account, and everything attached to it, from inside the app. Available in English, Spanish, French and German. Zdoku also plays in any browser at zdoku.com — the same puzzles, the same leaderboard, the same rooms.