All techniques
Last Free Cell
The Basics1 / 32Eight digits placed in a unit — one cell left.
The friendliest move in sudoku: when a row, column or box already contains eight of its nine digits, the last empty cell has no choice. Whatever digit is still missing goes right in.
You'll use this constantly — early in easy puzzles, and at the end of every puzzle when the board collapses into a chain of final cells.
See it in action
123456789
2
7
1
8
123456789
4
3
5
1
5
123456789
123456789
123456789
3
123456789
123456789
7
3
123456789
123456789
123456789
7
5
123456789
1
2
7
4
5
3
9
123456789
123456789
123456789
1
2
123456789
123456789
7
1
4
3
5
123456789
123456789
3
1
123456789
5
8
123456789
7
4
4
1
2
8
6
7
5
123456789
3
8
7
123456789
5
123456789
123456789
1
4
123456789
5
123456789
123456789
123456789
123456789
1
7
2
8
Step 1 of 4
The setup
Scan for rows, columns or boxes that look almost complete, then count which digit is missing. Step through this real position to see it happen.
Practice
One unit has a single empty cell left. Find it and place the missing digit.
Drill 1 of 29Tap the cell, then the digit — or type it.