The website (available here) is titled “Date A Time”, and it features a large, animated clock decorated with Roman numerals.
Fujimi Shobo, a publishing brand owned by the Kadokawa Corporation, is teasing a new development involving the Date A Live light novel series written by Kōshi Tachibana and illustrated by Tsunako with a mysterious countdown website.
Although there is no official confirmation yet, Japanese fans are already speculating that the countdown may conclude with the announcement of a new Date A Live anime adaptation.