How to Play
Understand the 9x9
The grid is divided into nine 3x3 sub-grids. Some cells are pre-filled with numbers to get you started.
Follow the Rule of 1-9
Place numbers 1 through 9 in the empty cells. A number cannot repeat in the same row, column, or 3x3 square.
Use Notes & Logic
Mark potential candidates in cells. Use the process of elimination to find the only possible spot for a number.
Sudoku Strategy
The Cross-Hatching Technique
Focus on one number at a time (e.g., all the 1s). Scan rows and columns to see which 3x3 squares are missing that number and where it could possibly fit.
The Sole Candidate
Look for cells that only have one possible number left after checking their row, column, and block. These "naked singles" are the key to unlocking difficult grids.
Work Small to Large
Start by filling the 3x3 blocks or rows that already have the most numbers filled in. This limits the possibilities for the remaining empty cells.