Nike products online different countries

I want to talk about a simple thing.  I used to live in the US, but now I live in japan.  In terms of product availability does nike have stock just for US, and just for lets say Japan?  Or does it have different pile of stock for each country thus making it more available let me know opinions are welcome.

I think japan gets early releases compared to the US, what i do know is the products in the U.K work out a lot more than what they are in most other places