Microsoft Sudoku is a free-to-play puzzle game developed and digitally released by Microsoft Studios (co-developed first with Arkadium, then with Behaviour) for the PC on March 6, 2014. It was later ported to Android and iOS devices and was made available on online browsers (via MSN Games).
A successor to the Windows Phone game Sudoku and part of the Microsoft Casual Games series, Microsoft Sudoku is a digital adaptation of the number-puzzle game Sudoku, tasking players with filling a 9x9 grid with a combination of numeric digits (with some of the grid pre-filled, higher difficulties making the board more ambiguous) so that each row, column, and 3x3 sub-grid have all nine digits.
Along with multiple themes (replacing numbers with different symbols), the game features Xbox Live support (including achievements and leaderboards), an alternate "Irregular" mode (where 3x3 sub-grids are replaced with irregular shapes), and a Daily Challenge mode (where players are given unique goals, such as completing certain areas of the board).
As a free-to-play game, it uses in-game advertisements which can be disabled by purchasing a monthly/yearly Premium membership.