When is a battle lost?

Perhaps the best definition for what constitues defeat for an army during this epoch lies with the principal philosopher of war, von Clausewitz.

“The result of the whole combat consists in the sum total of the results of all partial combats; but these results of separate combats are settled by different considerations.

First by the pure moral power in the mind of the leading officers. If a General of Division has seen his battalions forced to succumb, it will have an influence on his demeanour and his reports, and these again will have an influence on the measures of the Commander-in-Chief; therefore even those unsuccessful partial combats which to all appearance are retrieved, are not lost in their results, and the impressions from them sum themselves up in the mind of the Commander without much trouble, and even against his will.

Secondly, by the quicker melting away of our troops, which can be easily estimated in the slow and relatively little tumultuary course of our battles.

Thirdly, by lost ground.

All these things serve for the eye of the General as a compass to tell the course of the battle in which he is embarked. If whole batteries have been lost and none of the enemy’s taken; if battalions have been overthrown by the enemy’s cavalry, whilst those of the enemy everywhere present impenetrable masses; if the line of fire from his order of battle wavers involuntarily from one point to another; if fruitless efforts have been made to gain certain points, and the assaulting battalions each, time been scattered by well-directed volleys of grape and case;—if our artillery begins to reply feebly to that of the enemy—if the battalions under fire diminish unusually, fast, because with the wounded crowds of unwounded men go to the rear;—if single Divisions have been cut off and made prisoners through the disruption of the plan of the battle;—if the line of retreat begins to be endangered: the Commander may tell very well in which direction he is going with his battle. The longer this direction continues, the more decided it becomes, so much the more difficult will be the turning, so much the nearer the moment when he must give up the battle.”

David Chandler in Campaigns of Napoleon gives in Appendix I a table of probable casualties for a number of major battles in the Napoleonic era.  Some of these battles are reproduced below.

Chandler gave the following definition of casualties in his notes:-

“In the case of battles which lasted more than one day, the casualty figures are consolidated.  the percentage loss is calcuated on the basis of the highest number of troops that eventually fought.  The figures include prisoners taken on the day itself.”

Taking the figures above for the battles fought in this era and plotting them by their cumulative probability is instructive.

One can see that in the ‘average battle’ (50% in the chart)

a) The Allied forces suffered roughly 10% more casualties than the French.

b) The average battle resulted in casualty rates of 15% French and 25% Allied.

c) For both the French and Allied forces, most battles lie on a ‘normal distribution’, with a small high tail fraction with very high casualties (due mostly to pursuit after the battle was won, given Chandler’s definition of casualties).

The problem for a wargamer is how to allow for the second term from von Clausewitz , viz.

“Secondly, by the quicker melting away of our troops, which can be easily estimated in the slow and relatively little tumultuary course of our battles.”

This is surely some kind of loss of morale leading to mass panic, caused by local conditions of excessive casualties or loss of ground, threat etc.

We can use the information in the cumulative probability vs % casualties plot to ascertain likely levels that ‘mass panic’ would set in during a battle and prevent a wargame from being a straight fight to the finish.  We can use the allied numbers in the chart above to set probability levels likely to start a mass collapse in morale as a precursor to ‘losing’ a battle.

At the end of each move a test must be performed to see if the whole army suffers a collapse of morale. If the % level of casualties suffered exceeds for the first time the levels below, a random number is created for each unit and the following table indicates whether a morale crisis has happened.

[Note click on the table to enlarge it].

If the random number exceeds the level indicated for the level of casualties suffered, then the unit fights on until the next level is reached, when an assessment is made again. If the random number generated indicates a crisis of morale has occurred, then follow the guidance in the table above to show what would happen. In subsequent moves, all affected units can be rallied in the normal way. Note for a % casualty level above 40%, then an immediate crisis is likely to occur.

Should reinforcements arrive each move onto the battlefield, then the % casualties should reflect the new combined level of troops. In this way, continuous reinforcements ‘lift’ morale, or in this game, reduce the likelihood of suffering a collapse of morale.

Such collapses in morale were features of battles from the age of pike and musket to the end of the Napoleonic era.  The phenomenon is ageless.

“He that fights and runs away, may turn and fight another day; but he that is in battle slain, will never rise to fight again.”