"Correspondence" (also known as "La Corrispondenza") is the kind of romance the Japanese have traditionally loved to love — two people locked in a relationship that barely exists.

In this scheme of things, physical remoteness offsets but strengthens an emotional connection. It's a concept the Japanese have long revered, from as far back as the 11th-century days of the "Tale of Genji" and leading right up to present-day films, such as "Reisei to Jyounetsu no Aida ("Between Calmness and Passion," 2001) and the more recent "Hahato Kuraseba" ("Living With My Mother," 2015).

That could account for why tanshin funin ("bachelor husbands" who work in faraway locations while the wife and kids stay at home) remains an enduring part of the culture. It's perfectly acceptable for couples to be apart for a long, long time and some even believe it's the recipe for a lasting union.