Avalon Hill has successfully adopted this system since it first started with Tactics II. Many if not most of their games are based on this system. And many games by other manufactures also have similar systems. It is one of the most commonly used systems in board wargaming.
The mapboard depicts the area over which the conflict is fought. It usually depicts terrain features that affect movement and combat. Examples are natural features such as rivers, forests, mountains and swamps as well as roads, cities and ports.
The first generation of wargames had mapboards superimposed with a square grid that regulates movement and combat. Later wargames substituted that with a hexagonal grid that "measured" distances more realistically.
Counters represent the military formations available to the player. These may range from battalions to full corps depending on the game played.
Each unit had an id and unit type printed on it. In addition, the combat strength and movement factor are also reflected.
The game is played in turns. In each turn, players alternate moving his combat units and resolving combat. The distance(number of squares/hexagons) that each unit can move is determined by the movement factor of the unit. Each square/hexagon costs a certain number of movement factors to enter. If a unit has insufficient factors left, it may not make that move.
Combat is resolved by a single die roll and checking the appropriate odds column on the Combat Results Table (CRT). Odds are determined by the ratio of the total number of attacking combat factors to the total defending factors. Of course, the greater the ratio, the better results can be expected.
Victory is usually determined by the capture of certain objective spaces or the elimination of enemy units.
The above covers the basic classic wargame system. Most wargames have added more rules to better reflect the feel of the actual battle. Such "chrome" are just too numerous to delve into here, but these are the things that make one wargame different from another.