An open invitation is an invitation to a specific group of chessmail members. If you have created an open invitation, other members can see the invitation, accept it and begin the game.
You can send chessmail members personal invitations to start a game using their member names.
Send a personal email to a friend or acquaintance who has not yet signed up for chessmail, to invite them to a game.
Play against the chessmail online computer. You can choose between different engines for different levels of difficulty.