string of fate
The red string of fate (unmei no akai ito, 運命の赤い糸) (also called the red thread of destiny, red thread of fate, and other names) is an East Asian belief. According to this belief, every person in the world is connected to another by an invisible red string tied to the ankle or little finger of his or her left hand (though there are other versions of the legend). The two people connected by the red string are destined to be lovers. It is similar to the Western concept of soulmates or a twin flame. It is a concept very popularly referenced in anime and manga. Notable examples include Ai Yori Aoshi and Kimagure Orange Road, which frequently reference this concept. (Copied from Wikipedia.)
See also
The following tags are aliased to this tag: red_string, red_string_of_fate, and red_thread (learn more).
This tag implicates string (learn more).