One of the
key principles of
warfare is that when
military units get next to each other, they
influence each other. Why? Because, merely by its existence, a unit projects
force into the space around it.
The clearest example is when one unit wishes to move from point A to point C, only to find an enemy unit in point B. What is the poor army to do? They can't just ignore the enemy and move on. If they do, they will be attacked and destroyed! They must either:
- move out of range of the blocking unit
- delegate part of their force to interfere with the blocker's ability to project force
- close and attack
Hex-based wargames simulate this projection of force via a
concept called a
zone of control, or
ZOC for short. During the 1960s and 1970s, advances in wargame
design had created two types:
locking and
fluid ZOCs.
A locking ZOC is like a bear trap, like a tar pit. It is most often used in Napoleonic and American Civil War simulations. The ZOC typically extends into the six hexes surrounding the unit on the map. If an enemy moves adjacent to their hex, both units are stuck there -- neither can move until one or the other unit is destroyed.
This portrays the rigidity and superior firepower of 18th through 19th Century units. Once Napoleon tells the Old Guard to charge, the only way he can move the unit is by destroying what it is attacking. During this era, to retreat would result in the destruction of the unit -- you just don't turn your backs on an enemy holding muskets or rifles. Otherwise, "Le Guarde recule!" and the battle is lost.
A locking ZOC is also used in some operational-level simulations of WWII or modern tank warfare, where the same conditions of "no retreat possible" apply.
A fluid ZOC hinders the movement of opposing units, without forcing them to hold in place. If a unit could ordinarily move 4 hexes in one turn, then it would be slowed moving adjacent to an enemy unit, and only move 2 hexes.
This portrays the notion that a unit needs to pay attention to an enemy unit, and focus on remaining in good order. This is typically used in pre-gunpowder games, or the early musket and pike era, when guns had comparatively short ranges. It is also used in post-WWII games, where the speed of tanks and mechanized infantry allows it to bypass most opposition.
In games with locking ZOCs, there is almost always a rule stating that in combat, the defending unit may not retreat away from the attack into hex controlled by another locking ZOC. In these games, the primary tactic is to surround or enfilade the defender, and then apply sufficient force to cause a retreat. Since the defender cannot retreat into a ZOC, it is eliminated instead. This is a pretty accurate reproduction of contemporary doctrine.
An intermediate form of ZOC is the "semi-locking ZOC." It is similar to the locking ZOC, in that a unit that moves adjacent to an enemy unit must stop moving. However, the next turn, it is able to retreat in good order with no penalty -- usually, as long as it does not move into another ZOC.
Not all units have zones of control. For example, an infantry platoon with no anti-tank weapons is not threat to a tank, and will not exert a ZOC it. However, the tank will most definitely have a locking ZOC on the platoon, causing them to sit very still...