Sudoku seems so timeless that you'd be forgiven for thinking it's ancient, like backgammon and chess, but it originated in 1986, so it's newer than "Thriller" but older than the World Wide Web. Based on numbers, it's totally independent of language or culture, helping propel it to global popularity in newspapers, magazines, and software. Sudo Sudoku Puzzle Game is a free sudoku game offering classic sudoku puzzles in three levels of difficulty.
The puzzle's layout is very simple: a square, divided 3x3 into nine squares, each with nine squares itself. The numbers 1 through 9 run along the top edge. A menu bar included file tools for saving, loading, and printing games; a Check menu for checking individual squares or the whole sudoku; and a Tools menu offering three levels of play, Hints, and an option to generate a Running Sudoku you can e-mail to friends. The program also offers language options and a Help menu that includes rules. The objective is simple: fill each square's cells with numbers 1-9 and each horizontal and vertical line with 1-9 without repeating any number in either. The puzzle is partially completed to start players off, depending on the level of difficulty; the easier the puzzle, the more numbers are filled in already. You can click any of the large numbers and then click any cell to place it or right-click a cell and choose a number or clear the cell.
We quickly got the feel of Sudo Sudoku, starting with the easiest square and checking each one as we filled it. When we'd finished the central square (the hardest one) we checked it to verify the historic triumph. The more-difficult levels require players to juggle more numbers, but the rules are the same. Pressing Hint fills a square to get you started (or moving again). We could also print sudokus, even blank ones, for some old-school pencil-and-paper action. Sudo Sudoku has something to offer beginners and experienced players alike.