Troops lining up behind a wall, hedge or other obstacle can adopt a position to defend it. The front rank is moved right up against the obstacle to show this. Enemy wishing to attack the defenders can do so by charging them as normal. Attacking models don't have to physically cross the obstacle, indeed they are unable to whilst it is defended. Instead, the front rank is positioned on the opposite side to the defenders.

If attacking an enemy behind a defended obstacle, a 6 on a D6 is needed to hit them. This penalty applies to a unit attacking troops that have already taken up position behind the defended obstacle. The penalty does not apply to both sides in the combat even though the obstacle lies between them. The defending side has the advantage of already taking up a good position with its weapons sticking out or over gaps in the hedge or wall, whilst the other side must mount an assault in the face of a wall of sword points or spear tips. Flying models attacking enemy behind defended obstacles ignore the penalty.

The attacking side continues to suffer the '6 to hit' penalty until it wins a round of combat. Once the attackers have won the combat, they are assumed to have climbed over or onto the wall, and further combats are fought as normal. Chariots cannot charge models across defended obstacles, they would just be smashed to pieces.