Why has Japan never experienced a strong rural-to-urban shift in its population?

While agriculture was always important, Japan always existed as a semiurban community because the mountainous terrain forced most of the population to live along the country's coasts. Without a large rural population to begin with, Japan never really experienced the rural-to-urban shift common in the rest of the world.

Explanation:

the answer is title i subtitle b

what the first or next guy says