Sudoku rules illustrated
A completed grid highlights a row, a column and a 3×3 box to show the three standard Sudoku constraints.
Naked single Sudoku diagram
Eight digits in the row rule out every digit except 5 for the highlighted cell.
How to read this diagram
The row is missing only 5. Because the highlighted cell has just one remaining candidate, write 5 there.
This is a single-row teaching schematic. In a complete puzzle, row, column and box constraints all apply.
Image prepared by Sudokumax. Updated .
More to explore
All Sudoku images
X-Wing Sudoku diagram
A candidate diagram shows the four corners of an X-Wing and the sevens it eliminates in the shared columns.
Naked pair Sudoku: before and after
A row-level diagram shows two cells containing only 3 and 7, followed by the candidate eliminations they allow.