Heisei

The Heisei era is a term used to identify the previous political era of Japan. The Heisei series is named after the political Heisei era in Japan, which started in 1989 with the ascension of Emperor Akihito to the throne and ended in 2019 with his abdication.

Technically, the Millennium and MonsterVerse Godzilla films are also part of the Heisei era due to being released during the political Heisei period, but are considered to be separate series from the Heisei series due to having separate, distinct continuities.

Other major kaiju franchises have not followed this convention despite having similar hiatuses; for example, Gamera: The Brave is considered to be a part of the Heisei series, despite being released seven years after the previous film, Gamera 3: Revenge of Iris.