Hundreds of millions of people spend hours of their lives on Facebook every week, but there are some secrets that only a few of them have discovered. For example, last December, a member of the Chess subreddit community found a secret, playable chess game hidden in Facebook Messenger that anyone can play.

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In order to start a game, just open a Messenger conversation with a friend and type “@fbchess play” to begin. A chess board will suddenly appear in the chat box and the player with the white pieces moves first. But despite the fact that a visual representation of the board appears on screen, you’ll have to type in commands to make a move.

Each of the pieces is represented by a letter: P is pawn, R is rook, B is bishop, N is night, Q is queen and K is king. In the image above, if I wanted to move my pawn in the e column to e4, I’d need to type “@fbchess Pe4” or “@fbchess e4” into Messenger. It’s what’s known as Standard Algebraic Notation, but you can type “@fbchess help” if you need to see the rules.

You can also choose what color you start with by typing “@fbchess play black/white,” offer an undo of the last move with “@fbchess undo,” see starts from the game with “@fbchess stats” and resign with “@fbchess resign.”

No, it’s not the best way to play chess with a friend over the Internet, but it’s a fascinating, hidden diversion worth checking out.

Jacob started covering video games and technology in college as a hobby, but it quickly became clear to him that this was what he wanted to do for a living. He currently resides in New York writing for BGR. His previously published work can be found on TechHive, VentureBeat and Game Rant.