Flanking maneuver

A flanking maneuver is a specific military tactic used to gain an advantage over an opponent. It involves moving an armed force around the side of an enemy force. These sides are known as the flanks. Most armies concentrate their primary fighting strength at their front. By circumventing the front, a commander can attack an area where the enemy is least able to defend themselves. This movement can happen at the tactical level, the operational level, or the strategic level of warfare.

At the tactical level, there are three standard ways to perform a flank attack. The first is an ambush, which is a surprise attack from a concealed position. This is often used by smaller, mobile forces that use favorable terrain to hide. The second type occurs during an active engagement. One part of the attacking unit uses suppressive fire to pin the enemy in place. This prevents the enemy from retreating or changing position. While the enemy is busy, a second force advances to the flank to attack at close range. The third type is the double envelopment. This involves simultaneous attacks on both sides of the enemy at once.

History provides many famous examples of these tactical maneuvers. During the Battle of Cannae, Hannibal used a double envelopment to defeat the Roman army. This required widening his formations to create gaps, which weakened his center to allow the side attacks. At the Battle of Marathon, the Athenian leader Miltiades lengthened his line to prevent being flanked by the Persians. He did this by decreasing the depth of his center. In the pre-modern era, commanders used cavalry or chariots for flanking because they were fast and maneuverable. By the 20th century, armored vehicles like tanks replaced cavalry, as seen during the Battle of France in World War II.

Defending against a flank is just as important as attacking one. A commander must use the terrain to anchor their line. If a line is anchored to a mountain, a lake, or a gorge, the enemy cannot move around it. The Spartans used this tactic at the Battle of Thermopylae. Other leaders, like Henry V at Agincourt, used woods or marshes to protect their sides. Sometimes, an army can use a fortress or a walled city to secure a flank.

At the Battle of Waterloo, the Allied forces used farmhouses like Hougoumont to protect their sides. At the Battle of Gettysburg, the Union used natural strongholds like Little Round Top to guard their flanks.

When the terrain does not offer natural protection, armies use specific formations. Historically, cavalry was placed on the sides of infantry lines to guard against attacks. At the Battle of Cannae, Hannibal's superior cavalry allowed him to chase off the Roman cavalry and complete an encirclement.

In the hoplite system, the right flank was considered the most critical position. This led to a tradition of placing the best or most senior troops on the right. Some armies also used the echelon formation. This involves placing units in a staircase or arrow-like arrangement. If an enemy attacks the first unit's flank, the unit behind it moves forward to attack the enemy in return.

Flanking can also occur at the operational level. This means a commander tries to move an entire army to catch an opponent off guard. A famous attempt was the modified Schlieffen Plan used by Germany in World War I. The goal was to avoid the French armies by swinging through neutral Belgium. At this level, commanders also try to create second fronts. During World War II, the German Winter Line in Italy was anchored by the Adriatic and Tyrrhenian Seas. Successful operations, like the landings at Inchon, can break into the rear of an enemy force. These moves can force an enemy to divert resources away from the main battle.

Finally, strategic flanking occurs when entire nations or groups of nations surround an enemy. This often forces a country to fight on two fronts at once, which is a major disadvantage. During World War II, the Allies surrounded Nazi Germany from multiple directions. The fear of being strategically flanked has even influenced peace-time politics. During "The Great Game," the British and Russian Empires expanded into China. The British feared that Russia would surround British India from both the west and the east. This shows that the concept of the flank affects both the battlefield and global diplomacy.