The term ‘guerrilla warfare’ might evoke images of small bands of rebel soldiers stealthily moving through a dense jungle, executing surprise attacks on a more powerful enemy, then disappearing back into the forest as quickly as they emerged. 

You’re not too far off if that’s what you’re picturing. 

Guerrilla warfare, a form of irregular warfare in which small groups of combatants use military tactics like ambushes, sabotage, raids, and hit-and-run tactics, has long been the weapon of choice for the underdog.

Guerrilla warfare during the Peninsular War (Wikimedia Commons)

But why is this strategy so effective? Why do outnumbered, outgunned fighters often resort to these unconventional methods? And why do mighty, well-equipped armies find them such a pain in the neck to deal with?