OnlineSudoku.io Daily Sudoku

About OnlineSudoku.io Daily Sudoku

OnlineSudoku.io is a free browser puzzle site built around sudoku, with killer, jigsaw, samurai and mini variants and a set of other logic games beside them. Its Daily Sudoku Challenge is one page with one classic 9x9 board for the day, titled with the date, so everyone who opens it that day solves the same grid.

The board sits in the middle of the page with a number pad, an undo button and a print button. A timer runs while you solve, a score climbs as you place correct digits, and a mistake counter allows three errors. Above the board a countdown shows how long until the next puzzle, and a short line describes the day's difficulty, such as a gentle warm-up.

What sets it apart from many daily sudoku pages is the date picker: you can step back with Previous day or choose any date to replay an older board, and a View Archive link lists past puzzles. The page also keeps your current streak and best time, and it can be played in English and more than a dozen other languages.

It suits players who want a plain classic sudoku each day without signing up, and anyone who likes to catch up on missed days.

How to play OnlineSudoku.io Daily Sudoku

1. Open the Daily Sudoku page; today's dated board loads below the date picker.
2. Select an empty cell on the 9x9 grid.
3. Enter a digit from 1 to 9 with the number pad or your keyboard, so that no row, column or 3x3 box repeats a digit.
4. Use Undo to take back a move; three mistakes are allowed.
5. Fill every cell to finish the day's board and extend your streak, then use Previous day or the archive to play earlier dates.

Screenshots

Tips

• Start with the rows, columns and boxes that already have the most digits, where the fewest candidates remain.
• Pencil in candidates before trying pairs and pointing techniques; the page's own guide lists naked pairs, hidden pairs and box-line reduction.
• Since only three mistakes are allowed, place a digit only once you can rule out every other candidate.

Questions