Flanking Maneuver - Tactical Flanking - Defense Against - Formations

Formations

When the terrain favoured neither side it was down to the disposition of forces in the battle line to prevent flanking attacks. For as long as they had a place on the battlefield, it was the role of cavalry to be placed on the flanks of the infantry battle line. With speed and greater tactical flexibility, the cavalry could both make flanking attacks and guard against them. It was the marked superiority of Hannibal’s cavalry at Cannae that allowed him to chase off the Roman cavalry and complete the encirclement of the Roman legions. With equally matched cavalry, commanders have been content to allow inaction, with the cavalry of both sides preventing the other from action.

With no cavalry, inferior cavalry or in armies whose cavalry had gone off on their own (a not uncommon complaint) it was down to the disposition of the infantry to guard against flanking attacks. It was the danger of being flanked by the numerically superior Persians that led Miltiades to lengthen the Athenian line at the Battle of Marathon by decreasing the depth of the centre. The importance of the flank positions led to the practise, which became tradition of placing the best troops on the flanks. So that at the Battle of Platea the Tegeans squabbled with Athenians as to who should have the privilege of holding a flank; both having conceded the honour of the right flank (the critical flank in the hoplite system) to the Spartans. This is the source of the tradition of giving the honour of the right to the most senior regiment present, that persisted into the modern era.

With troops confident and reliable enough to operate in separate dispersed units, the echelon formation may be adopted. This can take different forms with either equally strong “divisions” or a massively reinforced wing or centre supported by smaller formations in step behind it (forming either a staircase like, or arrow like arrangement). In this formation when the foremost unit engages with the enemy the echeloned units remain out of action. The temptation is for the enemy to attack the exposed flanks of this foremost unit, however were this to happen the units immediately echeloned behind the foremost unit would push forward taking the flankers themselves in the flank. If this echeloned unit was to be attacked in turn, the unit behind it, would move forward to again attack the flanks of the would be flankers. In theory a cascade of such engagements could occur all along the line, for as many units as there were in echelon. In practise this almost never happened, most enemy commanders seeing this for what it was, resisting the temptation of the initial easy flanking attack. This prudence was utilised, in the manifestation of the oblique order, in which one wing was massively reinforced, creating a local superiority in numbers that could obliterate that part of the enemy line that it was sent against. The weaker echeloned units being sufficient to fix the greater portion of the enemy troops into inaction. With the battle on the wing won the reinforced flank would turn and roll up the enemy battle line from the flank.

In the Roman chequer board formation, readopted by Renaissance militaries, each of the units in the front line can be thought of as having two lines of units echeloned behind it.

As warfare increased in size and scope and armies got bigger it was no longer possible for armies to hope to have a contiguous battle line. In order to be able to manoeuvre it was necessary to introduce intervals between units and these intervals could be used to flank individual units in the battle line by fast acting units such as cavalry. To guard against this the infantry subunits were trained to be able to rapidly form squares that gave the cavalry no weak flank to attack. During the age of gunpowder, intervals between units could be increased because of the greater reach of the weapons, increasing the possibility of cavalry finding a gap in the line to exploit, and it became the mark of good infantry to be able to form rapidly from line to square and back again.