Introducing Digital Sudoku

Digital Sudoku is now available on Puzzle Lair. It brings a new kind of clue to a familiar puzzle, using the glowing parts of digital clock numbers to help you fill the grid.

If you enjoy Sudoku and want a fresh challenge, this is a good place to start.

What Is Digital Sudoku?

Digital Sudoku follows the usual Sudoku rules. Every row, column, and box must contain each digit exactly once.

The difference is how the puzzle begins. There are no starting numbers. Instead, every cell shows a faint digital 8, like the numbers on a clock or calculator. Some of its seven parts, called segments, are lit.

The digit you place must use every lit segment in that cell. Faint segments may also be part of the answer.

For example, if the two segments on the left are lit, the answer could be 6 or 8 on a board using digits 1 to 9. Both digits use those segments.

A pattern that looks like a complete number can still have several answers. A cell with the shape of a digital 7 could hold 3, 7, 8, or 9, because all four digits contain that shape.

How to Solve It

Start with cells whose lit segments leave only a few possible digits. Then use the row, column, and box to narrow those choices further.

The lower left segment is especially useful. Only 2, 6, and 8 use it. If that segment is lit and the row already contains 6 and 8, the cell must be 2.

Easy boards use only the digits 1 to 6. That makes some clues even stronger. If both left segments are lit, the answer must be 6, because 8 is not available.

After placing a digit, look along its row, column, and box again. Each answer removes a possibility from nearby cells. A cell with no lit segments can still be solved through these Sudoku rules.

Use pencil notes to keep track of possible answers. Tap Pencil or press P to switch between notes and normal entries.

What Makes It Different?

In regular Sudoku, a starting number gives you a complete answer for one cell. In Digital Sudoku, a clue gives you only part of a number.

You move between reading shapes and checking where digits can go. A small piece of a number can become enough to solve a cell once the surrounding grid fills in.

There is also an interesting challenge on the larger boards. The digit 8 uses every segment, so it fits any segment clue. You need Sudoku logic to find where it belongs.

Launch Details

Digital Sudoku launches with three difficulties.

Easy puzzles have a 6 by 6 grid, use digits 1 to 6, and have boxes two rows tall and three columns wide.

Medium and hard puzzles have a 9 by 9 grid, use digits 1 to 9, and have boxes three rows tall and three columns wide.

Every puzzle is verified to have exactly one solution that can be reached through logic without guessing.

In Check mode, you receive no feedback while entering digits. Press Check when you are ready to test the whole grid. There is no mistake limit. In instant mode, wrong entries are flagged immediately, and three mistakes end the puzzle.

Digital Sudoku is launching in beta. The rules and saved progress are stable, while the presentation may continue to improve.

Play Digital Sudoku or explore more examples in our Digital Sudoku solving guide.