Sudoku rules illustrated
A completed grid highlights a row, a column and a 3×3 box to show the three standard Sudoku constraints.
Locked candidates Sudoku diagram
A clean Locked candidates candidate diagram with highlighted pattern cells and crossed-out eliminations.
How to read this diagram
Within the top-left box, 7 is possible only in the two shaded cells of row 1.
That box must place 7 in row 1, so remove 7 from the rest of row 1 outside the box.
This is a schematic: only the candidates needed for the pattern are shown. It is not a complete playable puzzle.
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.