Sudoku Flags is ordinary sudoku with one twist: instead of the digits 1 through 9, each cell holds the flag of one of nine countries. The rules stay the same - every row, column, and 3x3 block uses each symbol exactly once. What changes is what you're looking at while you solve: instead of digits, you get Jamaica, Nepal, Luxembourg, Kenya. The game picks a fresh set of nine flags at random from the full list of 194 countries every time.

The logic is exactly the same as regular sudoku. And while you're placing flags in the grid, you end up learning what Togo's or Brunei's flag looks like along the way, no flashcards or memorizing required.

Sudoku Flags introduces you to the world's flags while you train your logic. This has a few practical effects:

• You get quicker at reading a political map and recognizing a country from its flag alone.

• Colors and symbols almost always trace back to a country's history, religion, or geography - every flag tells you something about the place it represents.

• Memorizing visual patterns exercises visual memory, which works alongside the logic sudoku already trains.

• Recognizing flags makes watching the Olympics and other international events more interesting, and travel more engaging once you start spotting familiar flags along the way.

Points from a completed game don't go to just one flag - they go to all nine flags on your board. Each flag stands in for one digit: every time you place it correctly, it earns a point (and loses one for a mistake). When you finish the puzzle, the completion bonus is split evenly between all nine flags on the board.

Once a month, the results come in: the leaderboard ranks flags by the total points they've earned across every player's board (it tracks each flag's own performance, not the country or its people). The winning flag for the month earns bonuses and prizes, split among every player registered under that flag. That way, every solved puzzle adds points to several flags at once, not just one.