There are few things more frustrating than loving an anime that has room to grow as a story, but never gets beyond one season of material. It’s arguably even more of an irritance when you know the second season would easily pay for itself. Fortunately, it’s very rare for popular anime to not get sequels (happens only about 20% of the time), and there are ways to predict which ones those will be. I like to think knowing softens the heartbreak.

Recently, I’ve been refining the list of anime which got sequels that I used for my column on the effects of licenses on anime getting sequels. Not to say that the original list was particularly off, but I’ve been reorganizing it in a way that makes it easier to make a smooth curve, en route to hopefully being eventually able to calculate the probability a given work will get a sequel just by plugging numbers into a formula. It’s not revolutionary work (it’s pretty obvious that anime that sell more discs are more likely to get sequels in general), but a lot of interesting data has fallen out of it. The biggest items of interest are the extreme outliers. Not only are these interesting to examine in their own right, but by examining them and drawing the right conclusions, I can add conditions and reduce my uncertainties significantly when I get to the point of being able to turn this into a formula. There are two primary categories of outliers; the commercial failures that still got sequels, and the commercial successes that didn’t get any. Today, I’m covering the latter category.

Below is the total list of 15 anime from 2005-2012 which got only one season, with no subsequent movie, despite selling more than 10,000 discs per volume:

Air
Angel Beats
Death Note
Durarara
Girls und Panzer
Inu x Boku SS
Kannagi
Kanon (2006)
Lucky Star
Mushishi
Persona 4
Suzumiya Haruhi-chan
Sword Art Online
Tari Tari*
Toradora

All but one of these series can be categorized into 3 principle groups, each offering a plausible explanation as to why a sequel hasn’t been made to date.

Group 1: Bigger Fish To Fry (9 shows)

Air
Angel Beats
Inu x Boku SS
Kannagi
Kanon (2006)
Lucky Star
Suzumiya Haruhi-chan
Sword Art Online
Tari Tari

These are anime made by studios that regularly churn out original 10k+ hits. Three studios working in this group (PA Works, A-1 Pictures, Kyoto Animation) have numerous major hits to their credit, and the fourth, David Production, got contracted to do bigger hit JJBA less than 3 months after Inu x Boku SS, tying the studio up for what now appears to be forever. The logic behind this category is simple; a studio with less-than-robust finances is going to take any financial safety it can grab a solid hold of, but those that make a habit of making original blockbusters don’t need to be dependent on one and can still be wildly successful without milking every show to the last drop.

This gets really interesting in Kyoto Animation’s case, where they’ve been perfectly willing to let the golden geese like Air, Kanon, Lucky Star, and the Haruhi-chan 4-koma (to a lesser extent) lie prior to hitting some significant commercial stumbling blocks in Nichijou and Tamako Market. Since Nichijou aired in 2011, both of their works to top 10,000 average per volume sales (Chuunibyou and Free) have gotten sequels. That’s a fairly small sample size, but it hints that they have adjusted their policies, becoming a bit more conservative in response to the lower sales totals of their weaker shows.

Group 2: No More Source Material (3 shows)

Death Note
Persona 4
Toradora

These are anime that faithfully followed their source material, to the extent that they ended with nothing left in the tank to adapt for a second season. This hasn’t always stopped studios (see OLM and To Heart for an example of this happening as a pure, unadulterated ass pull), but it generally is something of a deterrent.

Group 3: Recently Made/Continuing Source Material (2 shows)

Durarara
Girls und Panzer

This is the group for things that are still significantly too close to call dead. Durarara was made by Brains Base, which to be fair has a lot of other profitable ventures to its credit. The reason it’s not Group 1 is that I don’t think milking another cow to death would give qualms to the studio that squeezed 4 seasons out of Natsume Yuujinchou and has a very spotty sales history outside of it. I attribute this to the fact that there may well not be enough novel to adapt a full 2-cour season, and they may still be waiting on that to adapt. Girls und Panzer is just barely a year old, and Actas doesn’t have a particularly star-studded history that would indicate they’re comfortable with just rolling the dice next time around. I very much doubt it will be in this list in another 2 years time.

Group 4: You Tell Me (1 show)

Mushishi

If there is any logic behind this non-move, I don’t see it. Artland didn’t make those kind of mad profits with basically anything after this point, Hiroshi Nagahama didn’t helm another anime for 4 years afterwards, and there’s enough source material for another 25 episodes at the pace the series was being adapted. My best guess would be a Kare Kano-tier beef from either the mangaka or someone else high up in management that made a season 2 impossible.

Long story short: if a anime has commercial success locked up, still has source material left to adapt, and isn’t made by a perpetual heavyweight studio, then it’s almost guaranteed to get a sequel. Only almost, though, because sometimes things happen that are beyond the scope of conventional explanation. It pays to remember the prime law of statistics; you’re never 100% sure.

*I have Tari Tari logged as a 10k+ seller in my database, though the final total was closer to 9k, because not all volumes were out when I entered the data. It’s still generally applicable, as it’s still a huge success numbers-wise.