This is a nation of gaps.

When the term kakusa shakai came into vogue in 2006 — a fairly self-explanatory expression given that kakusa means "gap" or "disparity," and shakai means "society" — it was a clear sign of Japanese people having finally recognized that the notion of theirs being a hope-filled nation of upwardly mobile middle-class people was a myth.

In fact, being a highly stratified country, Japan has always been riddled with gaps. And its social strata, like layers of rock from different eras piled on top of each other, don't readily mix with each other.