NSA asked Japan to tap regionwide fiber-optic cables in 2011

The question to ask here is why these 'sources' are talking about a rejected request. The Japanese press is at least as subservient as the American press (the newspaper in question belongs to its fair share of kisha clubs), and this information is being leaked to it. Why?

The cynical explanation is that they are leaking for domestic consumption about one rejected request in order to make themselves look better, and it's entirely possible that there is otherwise deeply extensive cooperation which they are not mentioning. (What, the NSA waited until 2011 to ask for some wiretapping capability? What about all the decades before 2011? What about since 2011?)