Reserves—Destructive and Decisive Act
The combat he regards as settled by whoever has the preponderance of moral force at the end; that is, in fresh or only partly used up troops.
The combat itself he divides into a destructive and a decisive act. During the long destructive act, or period of fire preparation, the troops engaged gradually wear each other out, and gradually almost cease to count as factors in the decision. "After a fire combat of some hours' duration, in which a body of troops has suffered severe losses—for instance, a quarter or one-third of its numbers—the débris may for the time be looked upon as a heap of cinders. For the men are physically exhausted; they have spent their ammunition; many have left the field with the wounded, though not themselves wounded (compare, for instance, Eylau and the 1870 battles); the rest think they have done their part for the day, and if they get beyond the sphere of danger, do not willingly return to it. The feeling of courage with which they originally started has had the edge taken off, the longing for the fight is satisfied, the original organization is partly destroyed, and the formations broken up."
"So that the amount of moral force lost may be estimated by the amount of the Reserves used up, almost as with a foot rule."[63]
This goes on till, "In all probability, only the untouched reserve and some troops which, though they have been in action, have suffered very little, are in reality to be regarded as serviceable, and the remainder (perhaps four-sixths) may be looked upon for the present as a "caput mortuum."
Therefore the art of the commander he regards as "economy of force" during the destructive period; that is, to employ as few troops as possible, by taking advantage of ground, cover, etc., "to use a smaller number of men in the combat with firearms than the enemy employs," so that a smaller proportionate number of his own are reduced to a "heap of cinders" and more are left, more moral force, for the decision.
"Hundreds of times," he says, "a line of fire has maintained its own against one twice its strength" (e.g. the Boers).
To do this and yet obtain a good fire-effect demands very skilful handling of the troops, both on the part of the chief and subordinate leaders.
With the preponderance thus obtained the commander at last starts the decision. "Towards the close of a battle the line of retreat is always regarded with increased jealousy, therefore a threat against that line is always a potent means of bringing on the decision (Liao-yang, Mukden). On that account, when circumstances permit, the plan of battle will be aimed at that point from the very first." Or, "If this wear and tear and exhaustion of the forces has reached a certain pitch, then a rapid advance in concentrated masses on one side against the line of battle of the other" (i.e. the Napoleonic breaking the centre, of recent years thought almost hopeless, but revived in Manchuria with success, in the case of Nodzu breaking the centre at Mukden).
From what precedes it is evident that, as in the preparatory acts, the utmost economy of forces must prevail, so in the decisive act to win the mastery through numbers must be the ruling idea.
Just as in the preparatory acts endurance, firmness and coolness are the first qualities, so in the decisive act boldness and fiery spirit must predominate.
"The difference between these two acts will never be completely lost as respects the whole."
"This is the way in which our view is to be understood; then, on the one hand, it will not come short of the reality, and on the other it will direct the attention of the leader of a combat (be it great or small, partial or general) to giving each of the two acts of activity its due share, so that there may be neither precipitation nor negligence.
"Precipitation there will be if space and time are not allowed for the destructive act. Negligence in general there will be if a complete decision does not take place, either from want of moral courage or from a wrong view of the situation."[64]