Close Combat is a method of resolving combat that uses values more appropriate to restricted terrain. Every unit has close combat values. Close combat resolution will be triggered when one unit involved occupies a close combat hex, which are emplacements, small or above military bases, cities and towns, mountains, and dense forest. Close combat hexes may be viewed by pressing V.
Infantry generally have higher close combat values while tanks have much lower values. Be sure to avoid using tanks in close combat areas!