Thank you for always using back number official website and official fan club "one room".

We are pleased to announce that our official website and official fan club "one room" will be relaunched as a single website.

Due to the necessary updates, the website and official app will undergo maintenance on the following dates.

■ Maintenance period

Wednesday, August 6, 2025 10:00-16:00

*Please note that maintenance times may vary depending on the situation.

*During this period, access to the website and app, as well as all services, will be unavailable. We apologize for any inconvenience this may cause and appreciate your understanding and cooperation.

■Target Services

-back number official website

-back number official fan club "one room"

back number official app

The URL for one room will change after the renewal, so please update your bookmarks if you have them saved.

[Before Change] https://oneroom.info

[After change] https://backnumber.info

* The domain "oneroom.info" for email addresses sent from one room will not change.

This renewal will include improvements to make your content experience even more enjoyable, so please look forward to it!