Craftsmen discovered a way of taking the "pak dahl" wood, an extremely resilient birch tree that thrived in the ice storms and harsh seasons of Korea's mountainous peninsula, and tempering it to a hardness that could resist the edged weapons typical of the era.
Following traditions of weaponry at the time, Korean combative fans were often built with unique features chosen by their wielder and bore many possible combinations.
[1] Some combative fan users wove flexible metal ribbons along the outermost edge for cutting power, while others preferred feathers that hid finger-sized razor blades, which could cut deeply upon raking the fan's edge along a target.
Poison fans often hid deadly or stunning concoctions in small bladders or sacs which could be released upon spreading the fan open, allowing the user to gently direct a gust of irritants and toxins at their opponent over short distances.
Folklore and hearsay also suggests traveling merchants who possessed fans that had small compartments built into the cloth folds between the vanes of the fan, which held tiny explosive pellets that upon striking a surface would create a bright and dazzling flash of light.