Flanking maneuver

An example of this would be the Battle of Beaver Dams, where the British ambushed the Americans, halting their advance further inland to Canada.

Double envelopment can only be performed by widening friendly units or formations or opening gaps between them which results in weakening the center and similar battles to that of Gaugamela.

Flanking on land in the pre-modern era was usually achieved with cavalry (and rarely, chariots) due to their speed and maneuverability, while heavily armored infantry was commonly used to pin the enemy in place, as in the Battle of Pharsalus.

Armored vehicles such as tanks replaced cavalry as the main force of flanking maneuvers in the 20th century, as seen in the Battle of France in World War II.

A commander could prevent being flanked by anchoring one or both parts of his line on terrain impassable to his enemies, such as gorges, lakes or mountains.

Although not strictly impassable, woods, forests, rivers, uneven, and marshy ground can also be used to anchor a flank: Henry V at Agincourt.

In exceptional circumstances, an army may be fortunate enough to be able to anchor a flank with a friendly castle, fortress, or walled city.

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.

That prudence was used 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.

To guard against that, the infantry subunits were trained to be able to form squares rapidly 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, which raised the possibility of cavalry finding a gap in the line to exploit.

The most infamous example of such an attempt was the modified Schlieffen Plan used by the Germans during the opening stages of the First World War.

If successful, such operations can be shattering, such as at the Inchon, and break into lightly held rear echelons of an enemy when its front line forces are committed elsewhere.

In return, Scipio Africanus was able to defeat Hannibal not by trying to face him in Italy but by first undermining his power base in Iberia and then attacking his home city, Carthage.

The Cold War had its own Great Game, with the US and USSR competing for influence in Europe, Asia, Africa and Latin America.

The division of Europe, the proxy wars in Asia, and events like the Cuban Missile Crisis were all of great strategic importance to the two competing hegemonies.