Compared to conventional games of diplomacy or strategy, play-by-mail games (PBM) have some specific characteristics that make many players consider this form of playing as the most interesting of all.
First, as its name suggests, PBM uses the mail (or more commonly now electronic mail) for the transfer orders, and usually a computer to the moderating of the game turns.
For games designed specifically for PBM, it allows among other things to include in each game a number of players far beyond what is allowed in classic boardgames (where 6 is a limit of playability rarely exceeded), the average ranging from 10-20 to over several hundreds in some cases.
Furthermore each player may have only limited information about the game universe and some items may be gradually discovered as the player progress in the game.
Finally, the computer processing of orders would eliminate any risk of endless discussions on points of rules since we can be sure that any player in a given situation is (mis)treated with equal impartiality.
A game turn can usually be divided into four phases:
And it goes on until the end of the game or until the withdrawal of the player.
The sending of orders must absolutely be done before a deadline for each game turn; the interval between two turns can vary greatly depending on the factors involved (complexity of the game system, evolution of the game, constraints from postal services...).
Orders received by the referee after the deadline can not be entered, so players need to be extremely careful and should send them at least three days before the due date (one day before if using electronic mail).