Sudoku

×

Keyboard Shortcuts:

N add_box New Game

R restart_alt Restart Game

ink_pen Enter numbers

P draw Toggle Pencil Mode

H transition_dissolve Get a Hint

C check_circle Check Solution

I help Show Help Screen

1-9 pin Enter Number

Backspace backspace Delete Number

Z undo Undo

Y redo Redo

Sudoku Strategy:

Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid (also called "boxes", "blocks", or "regions") contains all of the digits from 1 to 9.

Basic Techniques:

Scanning: Look for numbers that are already present in a row, column, or 3x3 block. This helps eliminate possibilities for other cells.
Cross-hatching: Use scanning across multiple rows/columns to find the only possible position for a number in a block.
Counting: Count which numbers are missing from a row, column, or block.

Intermediate Techniques:

Hidden Singles: A number is a hidden single in a row, column, or block if it can only go in one cell within that row, column, or block, even if that cell has other candidates.
Naked Pairs/Triples: If two (or three) cells in a row, column, or block contain the same two (or three) candidates, then those candidates can be eliminated from other cells in that row, column, or block.

Practice is key! The more you play, the better you'll become at spotting patterns and applying strategies.