Heisei

The Heisei era (平成 Heisei), or Heisei period (平成時代 Heisei jidai), was a political period of Japan which started in 1989 with the ascension of Emperor Akihito to the throne, and ended with his abdication in 2019. Films produced during this era, such as those of the Godzilla or Gamera series, may be identified as the Heisei series (平成シリーズ Heisei shirīzu) of their respective franchises. While the Godzilla films of the Millennium series and beginning of the Reiwa series were released during the Heisei era, they are not counted in the same series due to coming after hiatuses in the franchise and not following the same continuity.

Similarly in the case of the Gamera series, both the Shusuke Kaneko-directed 90s trilogy and Gamera the Brave were released during the Japanese Heisei era, but are not considered to be part of the same "series" due to not sharing continuity.