The Seiun Award (星雲賞 Seiunshō) is a Japanese speculative fiction award for the best science fiction works and achievements during the preceding year. Organized and overseen by the Federation of Science Fiction Fan Groups of Japan (FSFFGJ) (日本ファングループ連合会議 Nihon Fan Group Rengō Kaigi), the awards were given each year at the annual Japan Science Fiction Convention. It is the oldest SF award in Japan, which was first given in 1970 at the 9th Japan Science Fiction Convention and has been awarded every year since that.
"Seiun", the Japanese word for "nebula", was named after the first and short-lived professional science fiction magazine in Japan, which appeared in 1954. The award is not related to the American Nebula Award.
It is similar to the Hugo Award, which is presented by the members of the World Science Fiction Society, in that all of the members of the presenting convention are eligible to participate in the selection process. But it is not strictly correct to call it Japan's "equivalent" to the Hugo Awards, as the Hugo Awards are open to works from anywhere in any language while the Seiun implicitly limited the area and the language like as the BSFA Award.