A quiet sudoku on notebook paper. A hundred levels lead from a 4x4 warm-up all the way to a 25x25 board, and every one of them has exactly one solution.

WHAT YOU GET

• 100 levels, board sizes 4x4, 6x6, 8x8, 9x9, 10x10, 12x12, 15x15, 16x16, 20x20 and 25x25 — the clues thin out as you go
• A daily puzzle in three sizes and three difficulties, the same one for everybody, new every day
• Notes, three hints per level, undo, board rotation and zoom
• One to three stars per level, measured against the fewest possible moves
• Every board you solve is kept as a picture on the achievements wall
• Play with the mouse or entirely from the keyboard
• 22 languages

HOW IT PLAYS

Pick a cell and type a digit, or use the number bar; the radial picker is there if you prefer it. Conflicting digits are marked, matching digits are highlighted, and the pencil mode keeps a tentative value in a cell until you are sure. The clock runs while you think, the board saves itself while you play, and you can put it down mid-puzzle and pick it up days later.

Keyboard: arrow keys move, 1-9 place a digit, Backspace clears, N is the pencil, U undoes, H asks for a hint, R restarts, Space pauses, F11 fills the screen.

MUSIC

Background music "Dream keeper" by zero-project (zero-project.gr), Creative Commons Attribution 4.0. Some sound effects by Kenney (CC0).

Keywords: sudoku, puzzle, logic, numbers, brain, daily puzzle, killer grid, 16x16, 25x25, offline game, relaxing

Developed by Vera and Josef Sejrek / Budbrain Software Contact: sudoku@budbrain.de