A secret chess game built directly into Facebook’s chat function and Facebook Messenger app.
To start a game, open a Messenger conversation with someone and type “@fbchess play”. A chess board will show up, and your game has just started!
This is not a drag and drop game, but you need to send some text command to play the game. Board will refresh with new image after each move. To play chess, you will need following commands,
P is pawn
N is knight
B is bishop
R is rook
Q is queen and K is king.
To move a pawn from the starting position, for example, you’d type “@fbchess Pb4”
If you get stuck you can always enter “@fbchess help” in the conversation’s text field. A list of commands and instructions will then show up.
This feature is available since a month, but no publicly advertisement for this. It was spotted on Reddit; the news passed relatively unnoticed until it was picked up by Lifehacker Thursday