Static and Dynamic Maps and Borders

Maps and borders are strange things.  We are acquainted with them relatively early in life and they serve as a useful way for us to adopt a more abstract view of the world around us.  In strategy and war games, the vast majority of our time is spent staring at a map.  How the map is designed then, becomes a crucial component of the player's experience, as it literally determines how we play, and think about, the game.  I think to describe a strategy game's map design we should answer two (slightly unrelated) questions:

1. How are borders and territories drawn?
2. How do players move their forces around?

Borders and Territory

There are two broad forms of borders in strategy games; static and dynamic.  A static borders system is fixed at game start and very resistant to change over the course of the game.  Any game that has pre-set territories for the player to conquer would be an example of a static borders system.  Crusader Kings II, Victoria II, and Medieval II: Total War are all good examples of static borders systems.

Victoria II is a good example of a static borders system in Strategy Games

A dynamic borders system is unfixed at game start and has some sort of mechanic to determine borders built into the game.  The Civilization series has traditionally used a dynamic borders system ever since the initial implementation of borders in Civilization III.

Civilization IV uses a dynamic borders system

Some games, or course, are moving in to the middle space between fixed borders and territories and dynamic borders.  An interesting baby step in this regard is the latest patch from Crusader Kings II, where duchies can migrate between kingdoms over long periods of time.  Since the kingdoms themselves are territories that can be warred over, this slow drift creates some dynamism in the fixed map itself.

CKII has fixed counties, but those counties can migrate between duchies which themelves can migrate between kingdoms over time.

Movement and Maneuver

Drawing broadly, there are two kinds of movement in strategy games: tactical movement and strategic movement.  Tactical movement is the kind of movement we think of when we read a map about an historic battle, such as Gettysburg or Waterloo.  Will the Cavalry be able to flank? Does the artillery have range on the enemy? Are the infantry dug in?  These are the kinds of questions we answer with tactical movement.  

On the other side of the coin is strategic movement.  Strategic movement works at a higher level of abstraction than tactical movement.  Have I brought enough Cavalry and Guns to attack this entrenchment? Do I have enough reinforcements in reserve to replace casualties? Do I have enough units on hand to push forward or should I fall back to friendly territory? These are the kinds of questions we seek to answer (or ask!) with strategic movement.

I think it's possible to draw another binary distinction in game design here with movement.  Is a player free to move his armies all about the map, or are his movement options fixed?  In a free-movement system, the player can move his units to any point on the map (or the map has so many points on it, as in Civilization IV or V, that it is effectively free movement).  In a fixed-movement system, the player can only move his units between territories, cities, or other significant features of the map itself.  Note that it is a continuum between totally free movement and totally fixed movement, and various games will land at different points on the continuum.

Generally, a fixed movement system will encourage (or force) players to think of movement in strategic terms, because there is no way to actually affect true tactical movement.  A free movement system, however, leaves open the possibility of tactical movements, but does not guarantee them.  Civilization IV's model actually favors tactical movement, but obscures that reality with the stacked-units mechanic, which encouraged strategic movement (mobilization and weight of arms prevails against the AI.  Humans however...)  Civilization V and Warlock: Master of the Arcane, by going to 1 unit per tile systems emphasized that the primary form of combat movement is tactical.

Those hills look like good defensive terrain, don't they?

Choices

The choice of movement system is not intrinsically tied to the choice of borders system, though one often informs the other.  The best choice, however, depends upon what you're trying to accomplish with the game.  Tactical movement adds yet another layer to the game, but can draw the player's focus away from overarching strategy and center him or her on developing generalship.  Strategic movement focuses the player onto logistics and removes some of the excitement of battles and warfare, as it becomes clear before the battle is even joined who is the prohibitive favorite to win (weight of numbers).  A lack of tactical movement can also reduce the influence of the map's terrain over the player's decisions and experience.  The movement system then, determines whether the player thinks more tactically or strategically.

In Medieval II: Total War, the borders are static, but players can move their armies freely about the map, setting up flanks and ambushes that effected the tactical battles.

The choice of a borders system is less clear cut in its effects.  Dynamic borders gives the player more ownership over the map itself, as the player's choices and actions are instrumental in shaping the map. Static borders make it easier for the player to set intermediate goals by breaking the map up into discrete chunks.  It feels like a trade off.  So the decision should be driven by what game the player wants to play.