What is an SDKU file? An SDKU file is a sudoku puzzle saved in a format used by Sudoku Solver, a sudoku solving app. It contains XML-formatted data that defines the puzzle's unsolved state. Sudoku Solver can automatically solve (most) puzzles saved in the SDKU format.

More Information Sudoku is a grid-based puzzle in which solvers must ensure each row, column, and 3 x 3 box includes exactly the numbers one through nine. David Hancock's Sudoku Solver is a sudoku solving app for Windows that attempts to automatically solve sudoku puzzles imported as SDKU files. Each SDKU file contains XML that specifies what numbers are placed where in an unsolved puzzle. Sudoku Solver users can import SDKU files and attempt to have Sudoku Solver automatically solve them, using its internal puzzle-solving logic.