Anime originated in Japan in the early 20th century as a unique style of animation, first used to simulate sword fights rather than entertainment. By the 1930s, animation had become a suitable form of entertainment in Japanese society. The first anime series to air in the US was Astro Boy in 1963, which was a successful show and sparked Americans' interest in more anime. Throughout the late 20th century, anime grew in popularity in America and studios began targeting certain demographics, like Sailor Moon attracting female viewers.