I've noticed that many anime have a character (usually female) wearing a chain (usually attached to a bracelet) that rattles when something "special" is going to occur. This could be: invoking a special power, the presence of a friend or foe, etc. (Anime examples: FLCL, Melody of Oblivion, Dears, etc.)
My question is: what's the significance of the "mystical chain"? Is this something rooted in Japanese culture?