I think all the games played in the cup starting from the Sweet 16 should be played in neutral arenas..
The final two rounds of the tournament (cup) will also be at a neutral site starting in season 8. For countries with four or more divisions, the final three rounds will be at a neutral site, and for countries with six divisions, the final four rounds will be at a neutral site.
Isn't the sweet 16 the 1st round of the cup in Japan? :)Actually, not sure why there's 3 divisions when there's only 39 active teams.