Military theory of skirmishing

(This is one of the topics a whole book could be written about, but I will try to shrink it to blog post size.)

Skirmishers are well documented since antiquity. Their contributions were likely overlooked by many contemporary authors because skirmishers had no high social standing. This is similar to how some authors pretended that medieval battles were just a class of a couple hundred or thousand knights each, when typically each knight represented a "lance" (a small group comprised by the knight and his followers).

a peltast (javelineer)
We have decent documentation of skirmishers from the actions of Iphicrates and Xenophon, though. Skirmishers of antiquity were often poor citizens who could not afford a heavy infantryman's kit or even slaves who followed their masters into battle and helped out with minimal kit.
The Roman Republic divided its citizens by their wealth (income) and the poorest ended up serving in skirmisher units; mostly slingers and javelineers. 
Skirmishers in antiquity were thus borne out of economic restriction and not necessarily always used for their effectiveness. Some such light troops / skirmishers were recruited as mercenaries, though (Balearic and Rhodian slingers or Cretan archers, for example). Such mercenaries were respected for their skill and apparently employed because of their cost efficiency. Moreover, Xenophon's expedition showed that light troops had a unique selling proposition: They were good at providing security, especially at climbing hills ahead and left and right of the army's march in order to avoid ambushes or harassing fires from them (compare Battle of Lake Trasimene).

The preferred Hellenic battle tactic before Philipp II was to set up two long phalanx lines and clash frontally with the enemy (with notable exception especially of the Battle of Leuctra with the famous oblique order that was later famously revived by Frederick II). The task of skirmishers was to harass and weaken with missiles. They used the lighter weight of their equipment for greater tactical mobility and thus the ability to avoid melee combat. Heavy skirmishers such as the later Roman Velites were also capable of decent performance in melee combat, but at most as addition to closed order tactics of the heavy infantry. Rarely did skirmishers compose the main effort in battle and as far as I know did there was but one well-documented battle in which skirmishers defeated a heavy infantry army without other arms doing the most of the job.
I have never found a mathematical way to express the dynamics of skirmishing in the Hellenic periods era in a useful way.

Parthian light (horse archer) cavalry practised a different kind of skirmishing. Their high value shock force (knight-like armoured lance cavalry) was best-used against hostile heavy infantry when it was not in good (closed) order. The light forces (light missile cavalry) thus attacked over and over again mainly to shape the battlefield for the shock forces. They injured, killed and despaired the enemy (Roman legionaries) to shape the battlefield for successful attacks by armoured lance cavalry.
I have not found a similar battlefield-shaping focus of skirmishing in Hellenic or Roman battles, though skirmishers always had the potential to entice an enemy into making an offensive move when it wouldn't prefer it otherwise.

Now fast forward to the 18th century and Napoleonic era. The skirmishers of this era were very different from antiquity. Moreover, the equipment of foot skirmishers of this era wasn't more lightweight than the equipment of line infantry. In fact, the Napoleonic era saw parts of the line infantry getting dispatched to serve as skirmishers. Skirmishing had become a tactic rather than an equipment issue.
The dominant factor behind the foot skirmishing of this era (and to some extent the Hussars' skirmishing) appears to have been the nature of closed order formations and the poor accuracy (and especially high dispersion) of most firearms.
Infantry in closed (linear) order (here grenadiers = relatively tall men)
The infantry of the era was employed in linear order (usually three ranks deep, but everything from two to six ranks were employed from late 17th century to Napoleonic era with three ranks being typical in the 2nd half of 18th century). This extreme discipline was rooted in an effort to maximise firepower with quick loading and firing when the blackpowder smoke of the previous salvo was gone. Such formations of hundreds of men in essentially 1.70 m by dozens of metres were easy targets even for inaccurate smoothbore muskets provided the shot wasn't from too far away (about 20% hit probability at about 230 m).
It was much harder to hit dispersed infantry at greater than about 60 m distance or so with the muskets of the time. The dominant skirmishing approach of the era in Europe was thus to have few men disperse and take shots at such easy targets. These dispersed troops would have less smoke problem themselves, but would need to be able to run to safety from hostile cavalry quickly.

French Napoleonic voltigeurs (skirmishers) in open order
The line formation could not really defend itself with full salvoes; to do so would achieve very little (maybe parity of kills), but it would wear out the flintstones of the muskets, foul the barrels of the muskets and disproportionally expend munitions (troops carried only about 40...60 cartridges into battle).* It would almost disable itself ahead of a clash with hostile line infantry. So this battlefield-shaping effect was avoided by employing  more limited countermeasures. The line infantry had small detachments step forward and fire a small salvo to discourage skirmishers. Sometimes a single peloton of the line would shoot a salvo. This did often not suffice, so the appropriate countermeasure was to meet skirmishers with skirmishers. This was already done in antiquity, of course. The fight skirmisher vs. skirmisher allowed for rifles to shine; their better (smaller) dispersion was of little consequence in a skirmisher attack on an infantry line, but highly prized in a fight between dispersed skirmishers.

This era allows for an interesting mathematical description of the mechanics of a skirmisher action, at least against an infantry line. A skirmisher vs. skirmisher action would lead to a Lanchester equation-ish description. Lanchester equations are not of much interest in regard to combat between skirmishers and line infantry because that kind of contact isn't about wiping either out.

The effective firepower (excluding the human factor) of the troops can be described as

effective firepower = qty of men x rate of fire x dispersion factor x target size (shortest edge matters most, so width for a single man but height for a line)

Now let's look at smoothbore musket skirmishers vs. infantry line (a Peloton). For skirmishers, it's like
effective firepower skirmishers = poor x normal x normal x good
Their effectiveness was exclusively from the target size, for they were fewer and the gun technology was identical to their opponents'.

For the infantry line (a Peloton) this reads as
effective firepower Peloton = very good x normal x normal x poor

I suppose it's not really necessary to replace the variables with figures - the abstract level is already informative. It suggests that there was little reason to expect skirmishers to kill more than they would be killed. The fact that the line infantry stood behind each other actually gave them a better ratio of shots fired to target area than the skirmishers had.
Source: Jean-Louis Vial of Nec Pluribus Impar
There were three important factors in favour of the skirmishers: They could often exploit cover (such as stone walls between fields) better than the line infantry (which had to prefer line order over exploitation of cover) and the line infantry should not react with its full potential munition expenditure for the reasons mentioned before. The third factor was that the line infantry could not sustain its effective firepower as they formed a smoke wall in front of themselves and thus increased their own effective shot dispersion.

Skirmishing on other days than battle days offered additional promise: Such skirmishing would typically be ambush salvoes, then the skirmishers would break contact. This worked in America, but not so much in Europe where the desertion-prone armies of the cabinet wars (prior to French Revolution) had to avoid woodland to keep desertion rates low.**

Rifled guns with their better dispersion (but much slower loading) were an obvious way of giving skirmishers not only an edge against other skirmishers, but also against infantry lines. Rifles had such a combination of "rate of fire x dispersion factor" that they could skirmish from an almost safe (against musket fire) distance and skill be effective. Rifles' accuracy also allowed for picking targets, so the riflemen could aim at high value targets (officers, some NCOs, gun crews and flag bearers), albeit this was frowned upon in Europe.

Mounted skirmishing was similar; its main purpose was to entice the enemy into wasting shots and fouling its guns. Hussars and other mounted skirmishers used carbines (smaller calibre, shorter barrel, mostly to exclusively smoothbore). They offered a larger target (+horse, almost no ability to exploit cover) and less firepower (shorter barrel firearm) than dismounted skirmishers did and their skirmishing was not highly regarded in mid-18th century Europe. The increase of the share of rifled carbines*** in the late 18th century has apparently not changed this much.


Skirmishing isn't much of a component in modern-day tactics field manuals for infantry or mechanised forces, but there is some potential.

One potential is about attrition of the opposing force by using small and stealthy/elusive teams to provide targeting information (and possibly battle damage assessment) for artillery and mortar fires.

Another potential is about delaying actions; small and stealthy/elusive teams might use disproportionate firepower (including calls for indirect fires, but also ATGMs, sniping, organic mortars), mines and other obstacles to force the opposing force into deploying and using combat tactical movements (exploiting terrain features for concealment, making use of smoke and so on rather than simply quickly driving along roads) to mitigate the threat. This leads to some attrition, but possibly more importantly it slows the opposing forces down.****

Swarming is another possibility. Swarms in the military sense are not simply loose groups or many small groups. Swarming is about pulsing attacks, similar to submarine wolfpack tactics. Many small elements unite in one effort by having the same target (a formation) and a narrow time window(s) for their (repeated) attack(s). I suppose this could be called skirmishing since it's about dispersed small elements taking on a formation of superior mass. Moreover, those small elements survive only if they avoid a too intense contact.
Such swarming can be combined with a lasting de facto encirclement (as opposed to the usually rather frontal approach of skirmishing against battle lines). A de facto encirclement puts the opposing force formation into a de facto moving pocket situation. It can move, but its external lines of communication are cut.

Finally, there's one element of skirmishing that's actually in at least some modern army doctrines. The U.S. Army with its formalised force-on-force training events at the National Training Centre***** emphasised counterreconnaissance a lot in the 90's and early 2000's. This was in part a lesson from their mock battles******, which had a defined duration of a reconnaissance phase before the main forces were supposed to enter action. This artificial rule elevated reconnaissance and thus counterreconnaissance to prominence. There were no dedicated counterreconnaissance units, so it was in part about reconnaissance forces fighting each other. That's a similar situation to 18th century and Napoleonic skirmishers battling between the two armies' infantry lines, of course.

additional related external links:


*: The fouling of the barrel was the main concern. An infantryman could have carried more than 60 cartridges and flintstones could quickly be exchanged with a screw mechanism after using up their durability of about 50 shots.
**: The more reliable (better pay, more comfortable job, less strict discipline, higher status) heavy cavalry provided security not only against hostiles, but also by guarding the own infantry against desertion as if the own infantry march column was a prisoner march column. They could not really do this in most woodland or swampland areas, of course.
***: Prussian example (Website in German)
****: An article that inspired me about this for decades: https://apps.dtic.mil/dtic/tr/fulltext/u2/a323568.pdf
*****: This changed during the Iraq occupation towards training for occupation and I have no idea how it developed since.
******: The term "counterreconnaissance" can already be found in a 1942 U.S. Army publication, though.


  1. Europe isn't going to be as full as it was during the cold war. Isolated pockets, isolated spearheads bypassing population centres. Plenty of room to manoeuvre.

    An all skirmisher land force may be viable. As self sufficient as possible, able to transit from relative safety and operate for 2-3 days before returning. COs capable of 'mission command' acting on initiative. Signature management, SIGINT, secure commo.

    This is where your hated gold plated 8x8s come in. The French proved they have the legs, have decent availability. The armament is sufficient for the task, armour allows them to operate where trucks would be suicidal. The French Jaguar 'armoured car' would seem suited in this task also.

    Problems? Fuel resupply, SHORAD. The Russians have rather a lot of helis.

    The wolfpack analogy may work on multiple levels. Large expanse to operate in. Meeting engagements rather than frontal operations. Satellites gone, air war stalemate rendering visibility close to zero. Unavoidably vulnerable 'fleet train'.

    Doesn't really hold up. But I cant see what a land barney between great powers would be like today. Missile exchange. Then the realisation that tin soldiers dont mean much when the entirety of your enemies critical infrastructure is vulnerable at all times.

    1. You are mistaken if you think WW3 would have been a high force density affair.
      NATO had a mere 26 divisions on a 1,000 km front in West Germany. There were plenty of gaps, and not enough troops to even only keep an eye on all the forestry roads.

      Suwalki Gap offers much higher force density scenarios than almost all of Cold War Germany.

    2. "Europe isn't going to be as full as it was during the cold war." That doesn't say the continent was going to be full. What that (is intended to) say[s] is that it is currently less full than it was during the cold war. So plenty of room on the flanks.

      All of this increasingly seems pointless.

      Where does conventional military power exist against nuclear armed great powers? What is the point of conventional strength? What is the point of conventional non nuclear military power? North Korea, Iran, Israel, Saudi, Pakistan. Stop playing games. Everyone nuke up, doesnt cost much relatively. The technology is no longer gated (despite the racist, revisionist, self regarding fetishisation of the yanks), Portugal could get nukes inside 9 months, Greece inside 6. Bulgaria has some decent universities, give them 7.5 months and some cases of Iron Brew and they'd get there. Screw it. Learn the lessons of the cold war.

      The Soviet battle plans are open source now (immediate nuclear prep strikes, poor Danes), same for the yanks (slightly delayed massive retaliation).

      I live inside the blast zone of a nuke aiming point so dont think I'm a disinterested party (and my father spent his entire childhood getting irradiated from 'our' nuclear weapons project).

      It's time for all great powers to get nukes. Screw the consequences. Building up conventional military power is a waste of time and money when it is supposedly postured to deter nuclear armed opponents.

      How the hell is a[n] (expensive) well trained, maintained and supplied pzh2000 cadre supposed to be anything but a joke to a leader who has topol launch buttons at their fingertips?

      Balance of terror 2.0. Slim Pickens was a genius.

      Whisper in the ear of Mutti and get her to swap the yankee bullcrap b61 for some tasty French fare. Save wasting forex on that black box compromised yank crap f18.

      I was terrible at predicting the future even before this virus, I'm even worse after it. Basic principles. Fight now. Fight in the past. Fight in the future. No retreat, no respite, no surrender. Eternal struggle. Come death, come sweet death.

      There is nothing else.

  2. Isn't the best way to defeat such a dispersed skirmish force a determined thrust by your own skirmishers, and if that fails, from the follow on force? If carried out correctly e.g. with counter-battery artillery assigned it might actually work out to the favour of the attacker.

    Moreover, if the skirmishers are too dispersed they become very easy to pick off. You're always mentioning modern ISR - small units will not have much EW equipment, engineering equipment, mine dispensers, and such like to prevent enemy maneouvre forces from identifying them, boxing them in, and turning them to mincemeat.

    In fact, wheeled motorised units (such as the 8x8s mentioned above) with good support could bottle up your skirmishers and neutralise them while the heavy armoured units conclude the campaign.

    Or am I missing something?

    1. I recommend Leonhard, "Principles of War for the Information Age" for this.

  3. As far as high intensity warfare goes..... i.e. vs China or Russia

    Skirmishers are probably only going to be only effective in mountainous terrain, forests, and urban areas in the modern day. In a sense they can only function if they can disengage, resupply, and re-engage at the time of their choosing. Any lightly armored force that is not under the protection of complimentary arms will be destroyed in short order. A case in point is how Wagner was systematically destroyed by airpower in Syria.

    Battlefield density also dictates the usage of skirmishers. In a highly packed area like a city with the commitment of tens if not hundreds of thousands of men there is no maneuver. Unlike formations that have the density, skirmishers cannot utilize the advantage of large skyscrapers or apartments in such a conflict as those would be leveled in the first week, or if they do there is no easy way to reposition or escape from well trained, well resourced, and numerous infantry.

    On the flip side in areas with too much opportunity for maneuver there is a lack of appreciable cover against modern sensor technology. At that point you are wagering that enemy electronic warfare is incompetent assuming you have the equipment to evade SWIR or FLIR.

  4. Thus the two main issues with modern version of the skirmisher at least up to the battalion scale is a decisive lack of firepower, lack of mobility (on feet or wheeled) in relative to contemporary problem (aircraft).

    Now if you were to get silly and arm the skirmishers with wheeled shorad in addition to tactical nuclear weapons (davy crocketts), a skirmishing force will overcome the two most pressing issues and now becomes a credible threat.

    Never say never after all.....we just woke up to negative oil prices and coronapocalypse this year.

  5. To some extent it comes down to how ATGM/Drone resistant the enemy's armour is. You have networked, non line of sight ATGW now with crazy ranges - even line of sight limited Javelin is pushing out to 4500 metres now with the latest lightweight CLUs. If you make the assumption that a fighting force ceases to be effective after 20-30% casualties, it is entirely possible that a fairly substantial attacking force could be neutralised before it even makes contact, and even in relatively open terrain. Someone above pointed to the need for effective wheeled SHORAD. Given lack of air supremacy by the defending side, something sensor agnostic, self homing and widely dispersed a good distance behind the line makes more sense than a vulnerable wheeled vehicle accompanying vehicle. The more dispersed the system is, the more survivable and the worse the tradeoff for enemies trying to neutralise it. Something like CAMM-L but with the addition of a passive imaging seeker version and individual, hidden launchers distributed and constantly re positioned by teams on trucks would fit the bill. That and something like LOSAT, only smaller, taking advantage of improved rocket technology, to overcome most of the vulnerability of imaging ATGW to various passive and active countermeasures.