In trying to figure out how many episodes make for an ideal and fulfilling anime, we need to go back to basics and understand how anime is aired and released to us, the viewers. Each season is called a cour – a term spanning just over 3 months in which an anime may be released and reach its conclusion. Anime are released at the beginning of a cour and usually end by the final week of the third month. Episodes are released weekly over the course of the three months – translating into anything between 10 and 13 episodes. Each cour is named after the four seasons – so Summer, Autumn (Fall), Winter and Spring are all cours. Summer kicks off in July and ends in September, Spring from September to December, Winter from January to March and Fall from March to July.

Over the course of the year, there could be anime which do not air solely in one cour and have more than the general 12 or 13 episodes. There are shows which are on air for two or more cours and ongoing which have any varying number of episodes depending on the length of the series. There are also split-cours anime which air for three months, skip the next three months and air again in the three months after that. Generally, each season or cour comes with a fresh batch of anime that we haven’t seen before, or a continuation of series past.

Anime can have its origins in just about any type of source material. There is anime based on genres of gaming, film and television; however, generally, anime will be based off manga. Shounen Jump is a publisher quite familiar with anime adaptations of popular anime as it has had series like Dragon Ball, One Piece, Naruto, and Bleach turn into successful animated shows. Depending on the amount of source material available, any individual anime could be long or short depending on how much of the source material is adaptable and how.

Sometimes, there isn’t enough source material to bring a series from beginning to end – production studios usually choose to create an appropriate ending which will diverge from the intended ending of the author. This was in fact the case for titles like Deadman Wonderland, Shingeki no Kyojin (Attack on Titan), as well as Hunter x Hunter, where the source material (manga in this case) had not reached its conclusion and therefore, the animation studios had construed endings for each respective show. The amount of source material is also a main factor in determining the overall length of an anime series, although it is possible for production houses to have their own idea of what constitutes as enough episodes for any given series. In many cases, the anime adaptation is outlived by the source material and tends to bear more of the story when it finally concludes.

Due to the reliance on source material which influences the way in which the story progresses, which affects the episode count. Some long-running anime such as Naruto and Bleach have several “filler” episodes which do not contribute to the overall story. Fillers are generally a way for major shows to keep their time-slot. Such shows generally have a vast number of episodes and air continually without going off-air for extended periods of time. Such shows include shounen giants like One Piece. Unfortunately there is no real way to determine the “perfect” number of episodes for any anime due to the fact that it would be completely dependent on a variety of factors, including the random will of the entity in charge of production.

In most cases, a production studio is supposed to gauge how much of the story it will tell in the space of 12 episodes. Due to the nature of anime cours coinciding with seasons of the year, a common trend is to have anime air over the course of 12 episodes, with the possibility of the anime to face continuation during other cours. A good example of this would be the recently-aired Bungou Stray Dogs, which saw its story being divided into two separate seasons, despite running in successive cours. Even though it seems like an industry standard to produce twelve episodes per season, it is worth noting shows which have not kept to the supposed standard.

A common practice in the anime industry is to produce extra material which quite often gives more substance and weight to a series or franchise. Some long-running shows have several OVAs – Original Video Animation, extra animation which present non-canon additions to a story, explore additional characters, or just give fans what they want: more. These are often released after a series runs through its cour or between arcs – it depends on what production houses are willing to achieve. They are generally distributed via home video formats such as DVD and Blu-ray and there is no real standard length of episodes nor is there consensus on how many OVAs any one series can have. OVA episodes are generally counted separately from the episodes which air on television.

When considering the artistry of an anime, everything is worth considering. There is a high chance that several different aspects define one’s experience of such a show. If need be, episode count could correlate with the in-universe progression of a story – it depends. A strange trend happening with anime which airs on the noitaminA sees anime span an anomalous eleven or twenty-two episodes; as opposed to the general twelve, thirteen, twenty-four, twenty-five or twenty-six which encompasses a large number of different series.

Studio Pierrot is an animation studio notoriously known for pumping long-running series with filler episodes and filler arcs. The anime which have experienced this (to the chagrin of most fans) include Shounen Jump legends Naruto and Bleach, which have engorged episode counts due to the vast number of filler episodes they have. Both have what could be considered an irregular number of episodes, spanning over 300.