Kriegsspiel (German: [ˈkʁiːksˌʃpiːl], "war game") was a system used for training officers in the Prussian and German armies. The first set of rules was created in 1812 and named Instructions for the Representation of Tactical Maneuvers under the Guise of a Wargame. It was originally produced and developed further by Lieutenant Georg Leopold von Reiswitz and his son Georg Heinrich Rudolf von Reiswitz of the Prussian Army.
von Reiswitz's system for simulating war was initially based around a specially designed table which he created for his King Friedrich Wilhelm III. The table (see photos on page 65, 67, 69 and 70) divided the game field into a grid system, a core element of many later wargame and roleplaying systems, and included different pre-cast terrain types used in modular combinations, as well as making use of special gaming pieces and dice. von Reiswitz' system also included the methods to simulate fog of war and communication difficulties, and a position of what he called a 'confidant', an impartial third party calculating and assessing the moves, analogous to the modern gamemaster.
The rules set, which was modified several times established several conventions for wargaming which hold true to the present day, such as the use of maps, color-coding the opposing armies as red and blue, using umpires, and uniform, complex rules for movement and combat. The accepted map scale was 1:8000 (though Georg Leopold von Reisswitz' initial design used a 1:2373 scale), and the time scale was 2 minutes per one turn. Blocks were used to represent units, which had different movement speeds, measured with the use of special compass, and which could even engage in short sprints. In addition to the 'gamemaster', a total of up to 10 players could play as a commander on one of two sides in the conflict. The rules assumed a hierarchy of command between the different players, and even stipulated that if different units were out of sight of each other, players would not be allowed to communicate commands.