When you receive a message from an opponent containing a move in one of your games, simply pipe the message through cmail. In some mailers this is as simple as typing | cmail when viewing the message, while in others you may have to save the message to a file and do cmail < file at the command line. In either case cmail will display the game using XBoard. If you didn't exit XBoard when you made your first move then cmail will do its best to use the existing XBoard instead of starting a new one. As before, simply make a move and select ‘Mail Move’ from the ‘File’ menu. See File Menu. cmail will try to use the XBoard that was most recently used to display the current game. This means that many games can be in progress simultaneously, each with its own active XBoard.
If you want to look at the history or explore a variation, go ahead, but you must return to the current position before XBoard will allow you to mail a move. If you edit the game's history you must select ‘Reload Same Game’ from the ‘File’ menu to get back to the original position, then make the move you want and select ‘Mail Move’. As before, if you decide you aren't ready to make a move just yet you can either select ‘Exit’ without sending a move or just leave XBoard running until you are ready.