This is coolbert:
An extract from an Internet web site the topic of which is reserves as allocated by the combat commander!!
Reserves as that term understood a concept unique to ground warfare.
Reserves during combat fulfilling a variety of functions to include but not limited to:
* Relieving spent and exhausted combat units.
* Plugging a breach in the defenses.
* Pursue a retreating enemy!
"It is basically for this reason that the maintenance of an 'unblown' reserve has historically been essential in combat, with battles often revolving around which side can hold out and deploy their reserves last."
"The reserve has always played a vital role in combat, but du Picq [Charles J.J.J. Ardant du Picq] was one of the earliest advocates not only of 'holding out a reserve as long as possible for independent action when the enemy has used his own,' but he also insisted on the revolutionary concept that this process 'ought to be applied downward' to the lowest levels."
"He [Ardant du Picq] also perceived the technological process of increasing lethality on the battlefield which continues today. 'There is more need than ever to-day, for protecting… the reserves. The power of destruction increases, the morale [of human beings] stays the same.'”
"Clausewitz further understood and put great emphasis on the danger of reserve forces becoming prematurely enervated and exhausted when he cautioned that the reserves should always be maintained out of sight of the battle."
Denying the enemy commander [Napoleon in this case at Borodino] the use of his reserves a dynamic stratagem quite often a crucial factor during combat.
As described by Suvorov:
"Think of the battle of Borodino and the cavalry raid carried out by Uvarov and Platov on Bonparte's rear. That was 'knight's gambit' for you in both meaning and form . . . The Russian cavalry neither fought nor charged, but simply appeared in the rear and that was that, but their appearance stopped Bonaparte from sending his guard into battle. And in many respects this one move decided both the battle and the whole destiny of Russia."
"Borodino - - Afternoon: North"
"By noon Prince Eugene [French] was preparing for a second attack on the Grand Redoubt [Russian strong point], but his plans would be delayed by a daring Russian cavalry attack. General Platov, the commander of the Cossacks, had spent part of the morning examining the lower reaches of the Kalatsha River. He had made two key discoveries - the river could easily be forded by cavalry and it was undefended by the French."
"Platov's Cossacks crossed the stream some way to the north of Borodino and threatened the French left-rear . . . The Russian cavalry did remain on the north bank of the Kalatsha for most of the early afternoon and wasn't recalled to the south bank until about 4pm. Some of the Cossacks may have stayed on the north bank for much longer."
"At the time the Russian high commander was very unimpressed with the cavalry raid . . . Only later did the Russians realize how much they owed to this cavalry raid. The French over-reacted, sending seventeen cavalry regiments north to deal with the perceived threat. Eugene's attack on the Grand Redoubt was delayed for two hours and Napoleon became even more convinced that he needed to keep the Old Guard out of the battle."
Understand also that Napoleon at Waterloo unable to commit his Imperial Guard units held in reserve as he so wished that amount of fully concentrated and focused energy necessary for final victory lacking.