Seiun Award

The Seiun Award (星雲賞, Seiunshō) is a Japanese speculative fiction award given each year for the best science fiction works and achievements during the previous calendar year. Organized and overseen by the Science Fiction Fan Groups' Association of Nippon (SFFAN; 日本SFファングループ連合会議, Nihon SF Fan Group Rengō Kaigi), the awards are given at the annual Japan Science Fiction Convention. It is the oldest SF award in Japan, being given since the 9th Japan Science Fiction Convention in 1970.

"Seiun", the Japanese word for "nebula", was taken from the first professional science fiction magazine in Japan, which had a short run 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, though it is not a one-on-one comparison as the Hugo Awards are open to works from anywhere in any language, while the Seiun is implicitly limited to works released in Japan and written in or translated to Japanese.

A professional work or achievement which appeared for the first time in the previous calendar year may be considered eligible. The eligibility of magazines is determined via nominal publication date, which often tend to be a month or two ahead of the actual date due to Japanese publication customs.

There are no written rules about word count for literary fiction categories, so that the decision of eligibility in that regard is left up to the voters.

Usually in spring, SFFAN issues reference nominee lists for reference in each category, which is chosen by the preliminary vote of their member groups. However, voters can cast their ballots for any eligible works outside of the list in the final ballot.

With consideration for voters' availability, a work which appears in a magazine (such as a part of serialized works or short story) or released as audio-visual media (such as a TV show or film) but wasn't chosen for the reference nominee lists may be eligible again if published as a book or released in any other media format.

There are effectively no official English names for categories, so they vary depending on translators. For example, "Long Work" may be written as "Long Story", "Long Form", or "Novel"; "Short Story" may be referred to as "Short Form" and so on.