Did either side ever employ "Reverse Slope" Tactics?

[Luke Freet]

For a war being fought with slightly updated Napoleonic-era tactics, I am curious why I rarely ever read about units utilizing reverse slopes like Wellington was known to use in the Peninsular War. I'm guessing my readings aren't 100% and I may have missed a battle or two where one side or the other did just that. I imagine it would have been much more useful for the Confederates, who generally had poorer artillery compared to the Union and lacked a lot of entrenching equipment. This may be colored by my readings on the Army of Tennessee, who were worse off than their Virginian counterparts, but from what I had read, it seems they suffered heavily during the Atlanta Campaign from Union artillery, which often drove them out of positions as often as flanking maneuvers did.

 

[Saphroneth]

For what it's worth, Wellington's ridge at Waterloo is actually a bit meh compared to the ridges he'd used in Spain (which were steeper and sharper). The fundamental principle though is pretty simple - direct fire weapons can't physically hit you and indirect fire is unobserved and thus very inaccurate. The primary downside is that it's fiddly - you can't rely on your units automatically observing the enemy's approach and reacting accordingly, and in addition you need a security line to make sure the enemy doesn't just take full control of their side of the ridge.

But the psychological impact is very important (battles, after all, are won by making the enemy run away). If done right, the defender's security line exerts psychological pressure on the attackers with skirmishing, meaning that the attacker is in combat while the defender's main strength is not. Then the defenders unmask and fire, which is sudden surprise and causes the attacker to recoil; at this point the defender could simply win a firefight or they could launch a (short) charge to rout the attacker during the moment of confusion.

This is very different to what happens if the defender is on the forward slope. The defender is then liable to be bombarded with artillery, and so it's the defender who is in combat first (and thus suffering draining psychological pressure).