The current Japanese calendar. The current emperor Akihito declared the Heisei era after his father's death in 1989, ending the Showa era. Thus, western 1989 became Heisei 1, western 2000 was Heisei 12.
"Heisei" is written with two kanji that mean "peace" and "to become", so a liberal translation could be "may there be peace".