Throughout this period, Japanese anime production made a limited impact on the Northern American market. The most notable work were the television series like "Battle of The Planets" and "Star Blazers" in the 1970s and "Voltron" and "Robotech" in the 1980s. As a rule, the imported series were heavily censored to make them acceptable to parents; "Star Blazers" and "Robotech" were partial exceptions. Although their impact on the art in North America was minimal for decades, the distinctive nature of the anime series created a cult following that grew gradually until the 1980s when "Star Blazers" and "Robotech", with their complex storylines and frank depiction of violence, helped create the groundswell that would lead to the major influx of anime popularity starting in the 1990s.