The Red String of Fate, also referred to as the Red String of Marriage, and other variants, is an East Asian belief originating from Chinese legend. According to this myth, the gods tie an invisible red cord around the ankles of those that are destined to meet one another in a certain situation or help each other in a certain way. Often, in Japanese culture, it is thought to be tied around the little finger. According to Chinese legend, the deity in charge of "the red thread, often believed to be the the old lunar matchmaker god, who is in charge of marriages. The two people connected by the red thread are destined lovers, regardless of place, time, or circumstances. This magical cord may stretch or tangle, but never break. This myth is similar to the Western concept of soulmate or a destined flame.
—Julio Garcia