It just takes one simple step to unlock this hidden game.

All you need to do is: type "@fbchess play" and hit Enter, during a conversation, and a small square box would appear in the chat box.

Here's how to play: The person who initiated the game would be assigned "White" side, to make the first movement.

Although there is some standard algebraic notation like:-

B for “Bishop”

R for “Rook”

Q for “Queen”

K for “King”

N for “Knight”

P for “Pawn”

Pawn could be moved by issuing the simple commands with numbers.

For, e.g. If your first play would take the third pawn from the left and move it up one block, you would write: ‘@fbchess Pb4,’ or simply ‘@fbchess b4.'

You could refer to the help section by issuing the command "@fbchess help" for the possible commands to assist you throughout the game.

You can undo a move with "@fbchess undo" command or by clicking the "undo" button — but your opponent has to accept the request to undo. The game would also allow you to have a conversation during the game with your friend, resumes the game by issuing the game commands.

Note: It turns out that the commands are case sensitive. The board will update and notify you whether it is your turn to play.