Learn the most fundamental Sudoku techniques: Full House and Hidden Single. Master these to solve Easy and Normal puzzles with speed.
"Full House" is the simplest situation in Sudoku. It occurs when a row, column, or 3x3 block has only one empty cell left.
Since every row, column, and block must contain numbers 1 through 9 exactly once, if 8 numbers are already present, the 9th number is strictly determined. There is no guesswork involved.
Look at the first row. It has numbers 1 through 8. What's missing?
"Hidden Single" is slightly more advanced but appears very frequently. It happens when a specific number can only go into one specific cell within a row, column, or block, even if that cell has other candidates.
