The objective is to fill a grid with digits so that each column, each row, and each of the subgrids that compose the grid contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution.
Sudocu gadget will let you exercise your mind playing this famous game.
Run the .gadget file to start enjoying it immediately, or save it on your disk to install later.