Kayan

The reason for introducing the custom of wearing neck rings has not been fully understood.

An excerpt from the article 12 facts about Kayan
Anthropologists speculate that they may have acted as a protection against enslavement by other tribes. Some speculate that neck rings were supposed to make women resemble dragons, which are an essential part of Kayan culture and religion. They could also protect the neck from attack by tigers or simply increase attractiveness by visibly emphasizing sexual dimorphism. Tribeswomen claim they wear rings to cultivate tradition and beauty.