I randomly came across a side quest (jace and Kay in the school area)
During the tour Kay said something about always wanting to go to Japan at first I didn't think anything of it until we reached the pool area where one girl comments on jace's Japanese.
Earlier in the original story ai, hana, and the MC were hanging out in Hana's room when ai learns the MC used to travel and knows many language. Ai asked if the MC knows Japanese to which he replied yes, after answering her question ai asked if the MC could teach her Japanese to where he declined due to languages changing overtime.
So.. are we in Japan or not?
(Sorry for the long comment... I really hope I didn't bore you to death...)