If you’re using MyAnimeList or other anime databases to scroll through titles, you will have definitely come across the terms “OVA” and “Special”. The latter is easy to understand, but OVAs can be confusing, since they aren’t encountered in other media. “OVA” stands for “Original Video Animation.” Let’s unpack what’s the meaning of this, the purpose of OVAs, and what differentiates them from Specials.
To put it simply, OVA is anime episodes or films that are distributed for home-viewing without having been shown in movie theatres or aired on TV first. In the cases of episodes, the first part of an OVA might still be broadcast for promotional purposes, but the rest of the series will not.
In past decades, OVAs would normally be distributed in the form of videocassettes for VHS. Later, LaserDisc became a common format of choice before we shifted to the known-to-all DVDs. Well-known OVAs include the 10-episode series Hellsing Ultimate and the 4-episode Rurouni Kenshin: Reminiscence.
“Specials” in anime are not unlike TV Specials. They can be anime episodes that aren’t part of the original show and they can sometimes interrupt the normal airing of a show. A recent example would be the recap episode that was aired between episodes 5 and 6 in The Promised Neverland.
There aren’t really many restrictions as to what a Special or an OVA might entail; sometimes they are an extra episode that almost feels like part of the original series, or they can use the original premise and characters to tell a completely different story.
It’s possible that an anime is both an OVA and a Special. Such is the case with the Specials of the shōnen anime Kuroshitsuji, including the alternative universe story Ciel in Wonderland and The Making of Kuroshitsuji whereby the characters appear as actors who are interviewed about their roles.
Basically, an OVA can be a Special but a Special is only an OVA if it is originally intended for home-viewing and was never broadcast on TV or in the cinema before being distributed as such. This means that The Promised Neverland Season 2 Episode 5.5 - as the recap episode became known – is a Special but not an OVA since it was aired in the same way as the rest of the episodes of the season.
Unlike conventional anime episodes which are usually around 22-26 minutes long, OVAs can have any length, with the aforementioned Hellsing Ultimate having episodes as long as 55 minutes.
Since OVAs aren’t broadcasted on TV, they aren’t restricted by any conventions it might entail, allowing for greater creative freedom. At times, OVA’s can be an opportunity for creators to experiment and play with the source material – again, think of all the anime that got “Wonderland” OVA episodes, including Kuroshitsuji and Code Geass.
The lack of broadcasting can take away some of the pressure of producing "high-quality" work allowing the creators to have fun with the material. After all, OVAs are often parts of pre-existing shows and are meant for fans who are willing to invest in DVDs for the extra material of a story they already love. Therefore, quirky material that almost feels like fanfiction can find a home in the OVA format, while it wouldn't as easily make it to TV or the big screen.
Of course, in some cases, such as in Hellsing Ultimate, OVAs can make amends if a previous anime adaptation was unfaithful to the manga. Without restrictions of time and tv conventions, Ultimate managed to be what most fans consider a much better adaptation than the first Hellsing anime.
To wrap-up, “OVA” simply describes any anime episode of film that is originally distributed for home use rather than being publicly broadcast. As for the content, this is as diverse as the anime series themselves.