Defender places terrain and attacker rolls for edge, both modified by general grade.
How it works
There is no DBA aggression roll; the actual defender places terrain (using enemy terrain types if in the enemy's country). The attacker rolls for battlefield edge, but a D general cannot nominate a 6 side and an E general gets neither 5 nor 6. Defending D/E generals place 1/2 fewer optional terrain pieces; in Big Battles a superior defender rolls to choose his edge.
A defending "D" GENERAL places 1 less optional terrain piece than normal; an "E" GENERAL places 2less features.