Terrain comprises the bulk of the playable space on most maps in Advance Wars and Advance Wars By Web and is a highly important consideration in any battle. Terrain as used here refers only to natural features and elements on a map - for Properties and their functions, please visit that page instead. However, all of the concepts discussed in this article do still apply to properties as well.
Each type of terrain has their own different combination of defensive benefits (shown by a number of defense stars) and movement costs for different Units, separated by movement type, and some have unique attributes on top of this. Certain COs may have an affinity for one or more types of terrain, and more broadly the arrangement of terrain on a map can have a significant impact on the balancing between COs who favour certain kinds of maps over others.
List of Terrain
The attributes for a particular tile can be seen in-game in the small window to the left of the game map when mousing over it.
The number of Defense Stars denotes the defense bonus a unit receives when they are attacked while standing on the tile, with each star giving an additive +10% defense. This is what contributes to the terrain defense variable in the Damage Formula and means that heavier terrain with higher defense star values are always preferred when fighting from. This defense is, however, affected by unit health, with each point of health loss reducing the terrain defense received by a multiplicative 10%. For example, a 5HP unit in a Forest (that gives ) will only receive 10% defense rather than 20%.
Lash has an affinity for defense stars, gaining +10% attack for each defense star a unit has and doubling all defense stars when her SCOP Prime Tactics is active, potentially giving as much as 80% defense for a full-health unit situated on mountains or the Headquarters.
Movement Costs describe the difficulty of traversal a particular unit movement type experiences crossing a particular type of terrain, with some types having lower costs than others. The most universal movement type is Air, which has a movement cost of 1 on every tile in the game except for Pipes. The only tiles with a movement cost of 0 for any unit are Black Tiles or Teleport Tiles, which are a glitch tile unique to AWBW that allows units to travel massive distances in a single move, though competitive maps do not feature them.
The distribution of terrain is an extremely important factor in considering the overall mobility of a unit on a map. As an example, consider a Tank, which has 6 MP and uses treads, traversing a series of Plains, which have a movement cost of 1 for treads. As such, the Tank is able to travel its entire length of 6 tiles in a single turn on Plains, allowing excellent freedom of movement. However, a Recon, which has 8 MP and uses tires, cannot do the same - Plains have a movement cost of 2 for tires instead of 1. As such, even though Recons have more base movement than Tanks, they can only travel 4 tiles instead of 6.
If a movement cost is not specified for a particular movement type, that terrain is considered illegal for units of that type and they cannot move onto such tiles. However, note on some maps predeployed units may still start off standing on illegal terrain.
Unique to capturable properties, capture points denote the amount of remaining investment an Infantry or Mech must put in to capture the property. It begins at 20 for all properties and most capture actions will deduct the capturing footsoldier's current health from the capture point total - when it hits 0, the property will be converted to the side of the capturing player.
For more information, see Capturing Properties.