Red thread of fate

The red thread of fate (Chinese: 姻緣紅線; pinyin: Yīnyuán hóngxiàn), also referred to as the red thread of marriage, the invisible string theory and other variants, is a Chinese belief originating from Taoism. It is commonly thought of as an invisible red cord around the finger of those that are destined to meet one another in a certain situation, as they are "their one true love". The Taoist deity in charge of "the red thread" is Yuè Xià Lǎorén (月下老人), often abbreviated to Yuè Lǎo (月老), the old lunar matchmaker god, who is in charge of marriages.

While Yue Lao remains an important deity in Taoism, the legend of his red thread of fate has been appropriated by cultures outside of China, often losing its religious context and association with him. In the original Chinese myth, the thread is tied around both parties' ankles, while in Japanese culture it is bound from a male's thumb to a female's little finger. In modern times, though, it is common across both these cultures to depict the thread being tied around the fingers, often the little finger. The color red in Chinese culture symbolises happiness and it is also prominently featured during Chinese weddings.

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 twin flames or a destined partner.