X.

X, also known as X/1999, is a Japanese manga series written and illustrated by Clamp, a creative team made up of Satsuki Igarashi, Nanase Ohkawa, Tsubaki Nekoi, and Mokona. It premiered in Kadokawa Shoten's shojo manga magazine Monthly Asuka in May 1992 and ran there until it went on hiatus in March 2003; it has yet to be concluded. The story takes place at the end of days in the year 1999.