Solve every sudoku

Sudoku has become an extremely popular pastime and is now as popular with puzzlers as crossword
puzzles and cryptograms. Nowadays, sudoku puzzles can be found everywhere: in waiting rooms, on the
beach, on the train and in airplanes. It is therefore fair to say that sudoku is the puzzle of the 21st
century. Where crossword puzzles require a large vocabulary, sudoku requires a wealth of solution