[Important] System Maintenance Notice
Thank you so much for always supporting back number.
This time, in order to improve our services, we will be upgrading our system to a new version.We will be performing nighttime maintenance on the following dates.
During the maintenance period, all services, including website access, login, and ticket pre-sale applications, will be unavailable.
We apologize for any inconvenience this may cause, and we appreciate your understanding.
■ Maintenance periodMonday, September 28, 2026, 1:00 AM - 7:00 AM(Scheduled) (Japan time)*The end time may vary depending on the progress of the work.
■Target Services
-back number official website
・back number official fanclub「one room」
back number official app