I've tried searching, but it seems that this isn't feasible or anyone has ever asked.
I'm going to Japan for eighty-something days, I'm doing an internship in Tsukuba. The internship program demands me to have an insurance, but a travel health insurance for so many days is pretty expensive. I've also read that NHI is quite cheap compared to travel health insurance, and that it's mandatory for people living for more than 3 months.
Is there any legal way to get NHI without being in Japan for more than 3 months?