Interestingly, "ano ko" rarely appears as a full character. They exist as an ideal—a collection of memories, photos, or old messages. This idealization protects the protagonist from discovering that the original person might have flaws. The fantasy remains perfect because it is frozen in time.

The keystone of the phrase is the particle combination "no kawari ni" (instead of). It announces a transactional swap. On one side of the equation is "ano ko" — "that person." In Japanese, ano ko carries a soft, distant intimacy. It is not a lover, not a spouse, but a that-person : someone observed from a slight remove, someone desired but not fully possessed. It is the object of a crush, a fading memory, a ghost at the edge of a commuter train window.