Aimer makes another regular appearance at this annual rock music event. These are the details found on the official website:

Event Dates: August 4-5, 11-12 2018
Venue: Hitachi Seaside Park
Time: 19:30
Festival website > rijfes.jp/

Other details will be released at a later date, including the exact date(s) and time of Aimer's performance.

Thanks wildthing for the tip!