As of 2018, how many teams currently compete in the highest level of 'Nippon Professional Baseball'?

The world series was never intended to be a global competition; the name comes from the original sponsor (Chicago World newspaper)

But I bet the Americans do not allow it to qualify for the “World” Series

doxierescued, I never heard of it either but I guess in Japan it's common.

I haven't heard of this either.

I love American baseball but I've never heard of this before