Vietnam is a better example here. They are continually afraid of Chinese invasion based on nearly a millenia of war preceding the wars with western colonizers. They are at huge disadvantage economically and technologically to China. So every single high school student and college student is trained in guerilla warfare tactics, the entire country is outfitted with secret military installations, and they are ready to resist any invader so intensely that there is no hope of a meaningful occupation no matter the seeming military asymmetry. This has protected them for the last 50 years other than a brief border war with China in the late 70s and some ocean territory incursions by the Chinese navy. Most of those were fought off by swarming them with fishing boats.