Sudoku technique: cross-hatching
Cross-hatching is the first Sudoku technique to learn: follow a digit across rows and columns to find the one cell in a box where it fits. Solving techniques · lesson 1 of 7.
The lesson in words
Pick a box and a digit it’s missing. The top-middle box has no 6 yet.
Every 6 elsewhere rules out its whole row and column. Cross them out in your head, like hatching lines across the box.
Find the 6s in the rows and columns that cross the top-middle box.
Try it: Put the 6 in the only cell of the top-middle box where it can go.
Pick a digit, scan the box, cross out the rows and columns. Next: cells with only one possible digit.