Sudoku Ace is new puzzle software based on Sudoku - a Japanese numbers game initially introduced in 1986. The Sudoku-mania really took the world over this year. For example, one of the major British newspapers The Telegraph, which started publishing the Sudoku puzzles in February, has received over 60,000 e-mails from the readers. And preparations for the worldwide Sudoku competition are well underway. The rules of Sudoku are quite simple - the player has to fill in a grid so that every row, every column, and every box contains all the digits one to nine. A tough Sodoku puzzle may take a few hours to solve. This is where the benefit of software comes in. Since Sudoku Ace isn't pen and paper, and there are an unlimited number of corrections that can be done. Plus the program allows saving the puzzle mid-game or asking for a hint. The number of "known digits" initially displayed varies from game to game. And, because Sudoku Ace is based on a proprietary algorithm, the quantity of different layout is practically endless. Another handy option is the program's Solve feature, which allows users to find a solution for even the most difficult Sudoku puzzles.