Tactics 101: 009. The Reserve
FOOD FOR THOUGHT REGARDING THE RESERVE
As you can surmise from the above discussion, a reserve is a necessity to keep flexibility on the battlefield. As we all know, conditions change with every event that occurs. Changing conditions result in changing plans. You must possess the ability to react and make your enemy react. J.F.C. Fuller states it better when he says, “… the value of a reserve cannot be exaggerated, for increased mobility carries with it the power of effecting innumerable surprises and the more the unexpected becomes possible, the stronger must be the reserves.”
A reserve must be an uncommitted unit. You can not give the unit a specified mission (task and purpose) and then also dictate that they are the reserve. This is bad tactics for several reasons. First, if the unit is planning and preparing for its specified mission it does not have the time to conduct planning and preparation for be-prepared reserve missions. A reserve force’s only role is to act as the reserve. It must plan and prepare for the anticipated missions it may be asked to execute. Second, if you tell a committed unit that it also is the reserve, you are likely to find it is incapable of being the reserve at the decisive point. If it is committed it has probably lost combat power and may be decisively engaged.
The usual answer you get when you ask why a reserve was not designated is that there was not enough combat power available to make it happen. If you start digging into the plan you find several things. First, in a defense you see that every piece of terrain is defended. As Jomini said, “I can only advise the party on the defensive not to divide his forces too much by attempting to cover every point.” In conducting some more analysis you will find areas where risk can be assumed. Your analysis on the enemy will aid you in determining where risk can be taken. Assume some risk and add flexibility to your plan by designating a reserve. Second, the plan probably does not utilize combat multipliers to their utmost. As we discussed in the last two articles, the combination of combat multipliers makes combat units much more lethal. Increasing your unit’s lethality should allow you to free up combat power. It seems many times when you see a plan with no reserve, the plan itself is based solely on attrition. Consequently, every single weapon system is committed to produce attrition. This is not a good way to fight!
Size matters when constituting a reserve. In regards to size, the most critical factors are your uncertainty on your actions and your knowledge of the enemy. The more uncertain you are to your actions and the enemy, then the bigger the reserve. In offensive operations, you will generally have a smaller reserve in a deliberate attack than in a hasty attack, since you have more detailed knowledge on the enemy. Doctrinally in a movement to contact, the reserve can be made up of between a 1/4 to a 1/3 of your force. In defensive operations, again, the more knowledge on the enemy and the less maneuver options he has then the smaller the reserve. The overriding factor in size is it must be lethal enough to successfully accomplish the things you may require them to.
THE DECISION TO EMPLOY THE RESERVE
• The Decision Point: The decision to commit the reserve rests with the commander. He must decide when and where to use them. The decision must be made in advance in order for the reserve to get where it is needed in time. The parameters that “trigger” the decision are part of the commander’s critical information requirements and should be closely tracked and reported.
• Enemy Situation: Where are the places the enemy will be that we might need to intervene? We will want to finish him off if he is culminating and we will want to halt his momentum if he is succeeding. We would look at the map to find places where one or the other is occurring.
• Friendly Situation: We will need to know the condition of our forces. If we have experienced success we my need a little extra combat power to push us over the top or if a unit in a critical location is fading then we may need to reinforce him. We may also experience a flank threat if an adjacent unit is collapsing or is observing the enemy in his area moving off to ours.
• Security: We need to be relatively certain that the enemy doesn’t know what our reserve is up to, where it is, when it is being launched, and where it’s going. If he knows two or more of these items than he could halt its commitment with air and indirect firepower.
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