
Sudoku rules illustrated
A completed grid highlights a row, a column and a 3×3 box to show the three standard Sudoku constraints.
A clean Swordfish candidate diagram with highlighted pattern cells and crossed-out eliminations.
Rows 2, 5 and 8 each allow 5 only at the six blue positions, all in columns 2, 5 and 8.
These three rows must occupy those three columns. Remove other 5s from those columns outside the selected rows.
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 .

A completed grid highlights a row, a column and a 3×3 box to show the three standard Sudoku constraints.

A candidate diagram shows the four corners of an X-Wing and the sevens it eliminates in the shared columns.

A row-level diagram shows two cells containing only 3 and 7, followed by the candidate eliminations they allow.