For those unfamiliar with the term, OVA means Original Video Animation (OAV means Original Animation Video... both terms are the same thing), and can be compared to... oh, say, straight-to-home-video release. The OVA was created in the early to mid nineties (they made each episode one at a time).
The flow of the OVA is very simple. The first three episodes introduce each of the three main goddesses one by one. Episode one introduces Belldandy. Episode two introduces Urd. Episode three introduces Skuld. The fourth and fifth episodes are where the major drama take place, and what makes this OVA really worth watching with its original material. The names of the episodes are
- Moonlight and Cherry Blossoms
- Midsummer Night's Dream
- Burning Hearts on the Road
- Evergreen Holy Night
- For the Love of Goddess
The OVA is more or less its own separate continuity from the manga or the new TV Series, but its widely accepted that it's - despite small inconsistencies - directly related to the movie. Overall, the OVA is a bit more romantic than the respective manga chapters - on the downside, there is not so much time for the humoristic part. Much of the development of the visual character design in the first five manga volumes is anticipated, which is a very pleasing thing, as well as the character design which gives us the divine Belldandy and a more confident Keiichi from the start.
While this change in character design can be seen from different perspectives, one is that Fujishima has not so much anticipated the character development of the first manga volumes but rather found the characters he wanted to write a tale about after these volumes and took them immediately for the OVA. The possible influence of the OVA's character designer Hidenori Matsubara, the director Hiroaki Goda and the others involved shouldn't be underestimated, too.
Even though the OVA was an artistic step forward compared to the beginning of the manga, the successive manga volumes have surpassed the OVA in visual design and character development as much as the movie has surpassed it in animation quality (due to the much higher budget.) Nevertheless, the OVA - accompanied by the TV series - remains a solid foundation for the modern Oh My Goddess canon just like Fujishima's and Matsubara's (among others') artwork for it constitute some of the very much liked incarnations of Keiichi, Belldandy and their companions.
The OVAs were domesticated in North America by a company called Animeigo, and the five episodes are released on two DVDs.