Young Frederick sat in his headquarters and issued instructions to his generals. Once his plans were made clear, his commanders quickly left to attend to their assignments and prepare for the next day's battle. All except one.
The young king noticed that the prince of Anhalt-Dessau still stood staring at the battle map. The Old Dessauer was shaking his head as he pointed to the map. "This hill is the key to your plan, my King. If you cannot hold it, we will be swept away before your attack strikes their flank."
Frederick knew Dessau still thought his role was to instruct him on the art of war and swallowed his anger as he responded to his old teacher. "I realize that, Leopold. You'll notice I've stationed the grenadiers there. My best infantry."
"Frederick, the grenadiers are in no condition to fight. You marched them all night to reach the battlefield and they are exhausted. They will crack at the first challenge."
Frederick rolled his eyes. "Even if that is true, they are supported by my guard cuirassiers. Their battle record is unmatched. "
"Frederick, their commander is a foppish coward. He can barely ride his horse during parades. The cavalry have no faith in him."
"Very well. Are there any regiments in my army you would recommend, Dessau?"
"Old man, they are fresh recruits, barely outfitted with their uniforms!"
"My king, they are indeed fresh men. Their health and enthusiasm is not ground down by the wear of the campaign. I walked through their campfires last night. They have few foreigners and are all recruited from Pomerania. The soldiers are in good spirits and eager to prove themselves."
King Frederick looked up the regiment in his muster book. "Leopold, my battle roster disagrees with you."
The Old Dessauer stepped so close to Frederick that his nose filled with the smell of musty uniform and stale tobacco. Frederick stumbled backwards. The Dessauer caught Frederick by his coat, pulled him close, and growled in his ear, "My King, your roster lies."
There have been many battles in history where veteran elite units underperformed and raw untested units showed surprising and unexpected quality in the heat of battle. A variety of factors can contribute to irregular performance in battle: lack of supply, heavy prior casualties, poor or excellent unit leadership, exhaustion, political motivation, regional rivalries, religious inspiration, luck, or extra ammunition. Many of these factors would be hard to detect by the army commander as he watched his troops march off the road and into battle line.
Units in Piquet usually have a Fire Die, a Melee Die, and a Morale Die. Modifiers in the game can improve or reduce the type of die the unit rolles for its test.
Piquet has a nice process wherein you roll on a d20 for the quality of your units before the battle to see just how good they are. Until you roll for their quality, you don't know what lies in the hearts of your little metal men.
The most likely result is Ready. Ready will give the units average dice for Fire, Melee, and Morale.
High quality rolls can give better results like Eager or Determined. A low quality roll might make the unit Battle Weary, a result that will give the unit bad dice.
The most interesting result is Vacillating. A Vacillating result means you roll again for the current quality, but the unit quality has to be checked again and can change when the unit is in its first combat.
Certain armies have modifiers to this Quality Roll to reflect the army's strengths and weaknesses. For example in 1862 American Civil War, Union artillery might add 2 to their Quality rolls while Confederate cavalry from the same period might also add 2.
You do have some intelligence about how good your units might be. There is a range of quality you can expect based on the unit's description. In the American Civil War, your infantry will usually be rated as militia, regulars, or elite. An elite unit will usually be pretty good even if it gets a Battle Weary result, but a Determined militia unit can be a match for it. Regulars are slightly better in melee than Militia.
Militia units tend to be the worst. Battle Weary militia infantry are unlikely to last very long in a fight.
I (along with many other Piquet players) take this a step further. I don't roll for the quality of my units until they have to use their quality to achieve something on the battlefield. So when I launch my main attack against my opponent, I just have to hope that brigade at the spearhead of the attack is feeling good today. If I get a Vacillating result, I don't record the unit's dice on my roster so I'll remember to check Quality for the unit again the next time it has to use dice for something.
So, if you want to defend a critical objective during a battle, do what the real generals did. Assign it to an elite unit and hope for the best. Of course, if your luck is anything like mine, your elite units will be Battle Weary and your Militia will be Determined fanatics.