Tactical reserves

I've seen very poor definitions of "tactical reserves", all seemingly derived from each other or from one common origin. For this reason I'll try to give a more satisfactory definition to get at the core of the idea:

"Tactical reserves are those subordinate combat forces that a commander strives to keep out of contact with opposing forces in order to commit them to action only after the area of their most promising employment has been identified or an opportunity for their most promising employment has arisen."
Tactical reserves have been most important throughout much of history. The layered Roman battle orders with Triarii in reserve and Alexander the Great's heavy shock cavalry are typical examples. Some other doctrinal systems such as the Greek polis' phalanx line knew no such reserves and were very susceptible to collapse and routing once one part of the formation failed.

In mobile warfare between armies consisting of mechanised brigades or smaller battlegroups one  would typically expect either clashes with extremely high attrition rates (1967, 1973 and 1990 examples) or contests between forces and tacticians of comparable quality in which the opposing commanders strive to fix or slow down hostile manoeuvre elements and especially the hostile reserves. The employment of the own reserves would be expected to yield the best results once the hostile reserves are busy elsewhere and unable to counter one's offensive move any more.
I remember a recollection of an army exercise in which an American officer was very proud that his division commander had the self-restraint to not tell his brigades to engage and destroy the red forces with brute force, but committed the author's brigade only until military intelligence reported that the opposing forces' reserves were already committed. The entire mission of that brigade was to draw in the opposing reserves, nothing else - and it was ordered to break contact once those reserves were understood to have been committed elsewhere already.

Let's for a moment believe that such a focus on tactical reserves as a major determinant of "success" in battle is appropriate. What are the consequences?

To commit an entire brigade merely to draw in equivalently powerful reserves sounds inefficient to me. What about committing much smaller forces, and feigning that those much smaller forces are actually a much greater threat?
A single battalion battlegroup could be sent to threaten some important objective (ammunition depot, army aviation forward airfield, corps HQ, river bridge etc.) in order to distract the reserves. It could exploit the terrain in order to be an unacceptably tough target of attack to merely equivalent-sized forces.
More friendly forces would then be available for the friendly tactical reserves, which could then be committed to exploit an offensive opportunity.

My old idea of manoeuvre elements (including armoured recce-like elements of at most company size) that don't fear being "behind" or "around" hostile brigades etc. interacts with this tactical reserves topic in an interesting way: Such elements could easily be told to converge on the hostile reserves and to keep them busy for a defined time window in order to achieve the same diversionary effect as would a much more substantial frontal attack of a brigade or two.

The key idea should be to achieve the desired diversionary effect with minimal resources (or rather minimal casualties). It would be of great help if the feint could gain the appearance of a more powerful force or at least of a major threat. This means the vehicle types, movement, electronic and fire support need to help generate this impression. It would also be of great usefulness if just any battlegroup could feign to be of double or triple strength instead of limiting such a deceptive capacity to but a few elements.

A commander and particularly his staff need a high level of self-awareness for this; they need to know what they would do if this feint was really a major action, or else they could not intentionally and consciously emulate this behaviour. Feints share the same disappointing fate with many other military preparations (such as prepared artillery missions); all-too often they fail to be effective because the opposing forces aren't predictable enough.

Tactical reserves and feints are not very prominent in field manuals about tactics, particularly for battalion  command and below. It seems that tactics course teachers, not textbooks, are meant to convey the importance and centrality of both tactical reserves and feints in "our" and "their" doctrines. This is somewhat risky, since it's this way less likely to be preserved as important part of the doctrine over generations of peace than if it was written down with more emphasis.



  1. The problem is that such forces are also prime targets for destruction in detail and that a daring move that works could have been a disaster if the opponent acted differently.

    So it is up to the commander to tailor his forces and understand the opponents psyche. The force can either deceive to be larger then it is, or be in a spot where they create issues for the opponent.

    The question is also whether feints are something that is working better on a higher, operational level. To get the opponent to commit the forces he holds back and then encircle them is a classic and it is far easier in that case to deceive the opponent as the first strike can be exactly the same as if it is a major offensive.

  2. Reserves to me were always situational.
    Alexanders use of his companion cavalry is impressive, but in reality, it was a tiny force, no more than 5% of the entire force, and thats assuming he had all 8 companions plus the double strength royal.

    A battalion battlegroup is likely to contain in the region of a third of the combat power of a Brigade.

    Its easy to see a situations in which the main line is beaten before the reserves can mobilise, let alone react.
    Unless the reserve is so massive that "main force" becomes little more than a screening force.

  3. Tactical reserves are important and being "behind" or "around" hostile brigades is also in OPFOR's mind.
    Maybe a detached 'tank commando' for subversive tactics. Indeed, commanders must have a high level of competence to be trusted to take initiative and decisions on their own.
    If one acts only by the book, one will get buried by the book. Many wars (of independence) would have never been initiated in a first place if we look only at the books. Because the books say ‘you cannot win, OPFOR is stronger’.
    Chances are that OPFOR knows both doctrines, and probably better than some in own forces. The difference is made by being unpredictable and knowing the OPFOR very well, then it is a question of exploiting opportunities with right timing, circumstances and luck too.
    One cannot predict the outcome of a battle in advance, when fighting a competent force.