I'm still trying to figure out if Gunner24 is asking the wrong question.
If I send a corps forward into battle, I expect them to stay there until they are no longer able to fight. When they start to weaken, I send in reserves. If I run out of reserves in that area of the battlefield, I've lost that fight. Reserves in the rear will have to take care of enemy units breaking through.
When a corps is in trouble and doesn't have reserves (another corps nearby behind them) there's not a lot you can do. Given the order delays, by the time any order you give to retreat gets there, it's probably too late anyway. And you never know when the corps commander will be able to handle the situation on his own, and an order to retreat would end up hurting you.
In most games, you get punished for keeping reserves out of the front lines. In HistWar it's essential to have reserves. It's nice to see it done right for a change.
Fighting a delaying action is one of those interesting tactical problems I've been wanting to do in the game. I haven't tried it yet. I think what I'll try first is to have two defensive lines, one behind the other several hundred meters apart, the best distance has yet to be determined. When the enemy forces start deploying and their pretty lines start to break up, order a forced march to the rear behind the second line and set up a new defensive line there. This will take careful timing with the order delays. Repeat as necessary. You'll need cavalry and artillery to help, and you'll probably lose most of them in the process.
You might try the same thing if you've stumbled across the entire enemy force at one end of the field and have to hold until your reserves can get there from across the battlefield.
Hook