Fun With Numbers: Some Visuals and Thoughts on Light/Serial Novel Adaptations from 2010-2016

Compared to manga adaptations and original anime, which tend to be all over the map, I used to view light novel adaptations as more of a solved problem – popular light novels almost always become popular anime. However, in the past couple of years I’ve seen that rule broken several times, and it’s worth it to go back and examine the data, especially as the slant of adaptations in the year 2016 was not only unprecedented, but also looks to perhaps be the start of a trend.

I’m looking specifically at non-sequel, serial novels with anime adaptations that aired between 2010 and 2016. I took the raw list and disc sales data from someanithing on February 6, 2017, and excluded all sequels and non-serial novels from the list, since they can’t really be measured on the scale we’ll be looking at. The novel sales data comes from the charts posted on myanimelist and aggregated here.

Of the 120 series remaining in the sample, I was able to get some sort of novel sales data on 97 (-23 with no data). 89 had novels chart pre-anime, 91 had novels chart post-anime. The difference comes from the fact that the following 6 series ended concurrent with or before the anime adaptation’s airing:

Hibike! Euphonium
Dantalian no Shoka
Maoyuu Maou Yuusha
To Aru Hikuushi e no Koiuta
Denpa Onna to Seishun Otoko

And the following 8 series only charted post-anime:

Mouretsu Pirates/Miniskirt Pirates
Outbreak Company
Hitsugi no Chaika
Inou-Battle wa Nichijou-kei no Naka de
Rail Wars!
Hai to Gensou no Grimgar
(Of these, only Grimgar’s post-anime volumes sold over 10,000 copies.)

Before we get started, the full sample of data can be found here. Now let’s get to some visuals!


1. What range of initial sales do LN anime come from? The answer has varied over the years.
presales-hisotgram-o30 presales-hisotgram-2030presales-hisotgram-u20
As you can see, the amount of adaptations of popular series have declined over the years, sharply dipping in 2016. This is easily explained by the fact that most popular series have been already adapted by now. The field was ‘tapped’, so to speak.

Histogramming disk sales confirms something we already kind of know.
disk-histogram-o30 disk-histogram-2030disk-histogram-u20
…Namely, that the outlook is better for anime when they’re adapted from already-popular novels.

When looking at the boosts in sales novels recieve compared with the anime’s disk sales…
pre-post-scatter boost-disk
…It is, again, easy to see the correlation.

So I mentioned the market was ‘tapped’. For a clearer idea of what that looks like, let’s highlight the last 2 years:
bty-fullbty-zoom bty-zoom_circle

Some Notes:
-While the charts show a clear correlation between novels with initially high figures and successful anime, a handful of notable exceptions have accumulated over the years. Adaptations of >20k novel series with subpar disk sales and minimal novel boosts include:
Shinrei Tantei Yakumo
Seirei Tsukai no Blade Dance
Sakurako-san no Ashimoto ni wa Shitai ga Umatteiru
Densetsu no Yuusha no Densetsu
Heavy Object

30k+ novels almost always seem to lead to hits (Yakumo excepted). The majority of exceptions here seem to come from that 20k-30k midrange.

On the other end, the novels with weaker pre-anime numbers that saw >4k disk sales and novel boosts include:
Amagi Brilliant Park
Jinrui wa Suitai Shimashita
Kono Subarashii Sekai ni Shukufuku wo
Log Horizon
Mayoi Neko Overrun

I noted this more crudely on twitter weeks ago when I first started research.

-Series that ended congruent to their anime have a spotty record in disk sales that likely understates their true strength. Stuff that gets animated is going to see its source material in bookstores, and not just the secondhand kind.

Maoyuu is unique among the novels that ended pre-anime in that it had a particularly popular manga, and we can easily observe a boost in sales there.
It should be noted that the existance of spinoff manga is hardly unique to this series, but spinoff manga is quite possible to miss as a significant revenue source owing to the incompleteness of manga sales charts that only track the top 50 in a given week.

-Amagi Brilliant Park came out of the gate selling 20k per volume, but initial sales dipped off for the second and third volumes. The first-post anime volume showed ‘recovery’ to those initial levels, which I count as a boost.

-These figures are all considerably understating overall totals. For an example where I can cite figures, KonoSuba’s best oricon chart appearance pre-anime was about 13k for the 6th volume, but the sales total at that point was already up to 400,000. Though the anime caused that total to surge to 2,000,000 in the anime’s immediate aftermath, making it roughly proportional to the 12k->59k per volume increase, we can’t assume that proportionality will hold in all cases. These just happen to be the best set of consistent figures we have.


-Depending on the source you’re citing, the cost of making a 12 episode anime varies somewhat. Some sources say it’s 250 million yen for a 12-episode series, some say it’s 10 million yen per episode (which would be 120 million for a 12-pack).

With so much happening under the hood, it’s of limited use to play the “match budgets to gross revenues” game, but we’re doing it anyway. According to our sources, the minimum for a 12 episode anime is 120 million yen, and 250 is a reasonable figure. Numerous sources of revenue have to match that over the full lifetime of the series for an average anime to be viable to adapt.

If a novel volume costs about 700 yen, there are 10 volumes in an average series, and we take the median amount of a novel boost at 9000 copies, that means an average anime bump could make a series *a minimum* of 63 million yen if things peak out where they do on the charts (HA).

The median for disk averages is about 2400. At 30,000 yen per set, that works out to 72 million yen. Those two lowball figures combined get you to the minimum, and a not-unreasonable factor-of-2 increase for the long tails of each gets you to the more commonplace 250 mil. So the system works. Whew.

It’s super-reductive to take the time to argue that anime can make money in the abstract – over a hundred shows continue to come out year-by-year. The only interesting thing here is how big a part the sales of light novels can play in making that balance sheet function; you really only need a thousand or so high-rolling fans to latch onto it if your series makes an average-sized splash. And the two groups, the casual masses and high-rollers, both play surprisingly big and similar-sized roles in doing so. This would suggest that fans could do to respect one another.

-Does adaptation length matter? The two strongest-performing adaptations of 2016 were far and away KonoSuba and Re:Zero, and they share very similar profiles. Per-volume novel sales pre-anime were between 5 and 15k, then surged to 50k+. Both disk averages were a little bit over 10k. The only big difference was the massive gap in tone, and the fact that Re:Zero had 250% more screen time. Despite having twice as many episodes, Re:Zero didn’t make twice as much money – as we discuss above, the novels are significant, and the novel boosts were the same.

If KonoSuba and Re:Zero represent the apex performance of ultrashort versus 2-cour adaptations, Tenkyou no Alderamin and Occultic;Nine represent the nadir; 1 and 2-cour adaptations (respectively) that sold triple-digit disks and made no appreciable impact in the novel area. Let’s take these performances as the worst case. In Occultic;Nine’s case, you’re spending twice as much money for the same fart of a result. Not great. However, though that elementary logic that would seem to push lower-risk 1-cour projects, the actual landscape last year wasn’t that different for serial novel adaptations last year than it was in 2010. 2010 had 2 proper 2-cour adaptations (Densetsu no Yuusha no Densetsu, Durarara) plus one weird outlier (Katanagatari) out of 13 total, 2016 had 2. Same ol’. 2015 had 2 (Heavy Object and Gakuen Toshi Asterisk) out of a possible 20, 2014 had 2 (Mahouka Koukou no Rettousei and Hitsugi no Chaika) out of a total of 18. It’s difficult to split hairs over whether there “should” be fewer 2-cour adaptations, as they’re rare enough to begin with that practical statistics can’t effectively be brought into the argument.

Perhaps more relevant to ask is whether there will be more adaptations with 10 episodes and fewer with 13. KonoSuba provides a clear example that you don’t *need* the extra 3 episodes to attract casual attention and get your money’s worth on the novel sales front (as does the early onset of Re:Zero’s boost, actually). But hey, maybe it just takes more time to tell a good dramatic story than it does to land some jokes. While I personally think the shows that get 13 generally use that time, and the length may contribute to a better fan experience, minimizing risk is likely to become increasingly more relevant in a light novel market that is increasingly tapped out of guarantees.

In general, we seem to be moving towards “anything can get an anime” provided the cost is cheap. Counting ‘OVAs’ that air first in theaters like Yamato 2022 and Mahoutsukai no Yome, we’re up to 10 anime movies premiering in February alone. Zegapain got a movie (which was hella clever in recycling its footage for cheapness and getting away with a good product), and Makoto Uezu is on record saying that if that can get a movie, anything is possible. And hey, at the same event he said that, fans were requesting continuations to Astro Fighter Sunred, Kamisama Dolls, and even Kirikumas.

5 thoughts on “Fun With Numbers: Some Visuals and Thoughts on Light/Serial Novel Adaptations from 2010-2016

  1. Several points (sorry this gets a bit ranty in places):

    – Why did you remove Gate as a “web novel” even though it has a light novel version? Sure, that’s where the series originated, but then so did Re:Zero, Overlord, Sword Art Online and many others.

    – Occultic;Nine, which you list as a 2 cour adaptation with no appreciable impact on the novel, hasn’t had a novel out since the anime aired.

    – There are all sorts of other factors – 8 or 9 days on sale is very different to 13 or 14. Likewise, having a LE on a volume can bunch up the sales in the first week. This is most notable with Haganai in that data – a series which we know had a very big sales boost indeed, but which appears to have had a big drop in sales due to the absence of a LE for vol 8. You could argue that this would roughly balance out over time and you’d probably be right. But you can’t then claim the series as an example of a poor boost just because it got unlucky with timing (see 2 points down)

    – Series that are longer at the time the anime came out will not see as much of the sales boost for the next volume, particularly if said next volume comes while the anime is still airing. HOWEVER, they will get bigger actual sales boosts. A 10 volume series at the time of an anime series starting that sees a 5k sales boost for volume 11 over the first 2 weeks has probably seen a sales boost from the anime of >5k per volume. Factoring in that Oricon doesn’t report all sales, or any ebook sales, and a figure of 5k is probably more than 100k all told. Then again you also ignored the portion of the sale that is taken by retailer, distributor, printer etc. and used abnormally high volume prices. So this section is basically useless.

    – For something of an example of the above, you use Alderamin as an example of a series that does badly. Yet in the first month it got 44k sales (including a new volume that had reported sales of 11k and total sales of <18k) and in the second it got 28k. On the 3rd month it failed to make the series rankings threshold of slightly over 21k, but was probably not far off. If we say that's about 70k (a very conservative estimate) in backlog sales as would be reported by Oricon while the anime aired, assume Oricon reports 70% of physical sales (a reasonable assumption) and that physical sales account for 2/3 of the total (more of a guess) then that's a sales boost of 150k. For something that you are using as an example of the NADIR of sales boosts. Although a large part of the reason for the lack of apparent boost is that the pre-anime figure is for 9 days' sales, whereas the post-anime figure is just 4 days. In practice the sales boost was probably about 50% or so – so (coincidentally) around the 5k boost that I mentioned above, with around the same number of volumes. A good example of a poor sales boost would be Dragonar, but then with the series already on 16 volumes when the anime started, what do you expect for the boost to the latest volumes? Even with those extra volumes, though, it was selling considerably less backlog sales per week than Alderamin was managing with several fewer volumes.

    – KyoAni novels should probably be removed from the data as most of their sales are via the KyoAni store which does not report to Oricon. Hence why they are N/As.

    – Some of the N/As are entirely down to MAL not listing them, which I assume is where you got your data from. HaruChika is one example, although that's also a series that hasn't had any new volumes since the anime. Hyouka is another example (although they included it whilst the anime was airing), although the "after" volume came out more than 5 years after the anime ended.

    – Kami-sama no Inai Nichiyoubi shouldn't be N/A. There was just a VERY long gap between volumes 8 and 9. The volume before (volume 8) sold 34586 in its first 2 weeks. The volume after sold 26552. This doesn't mean that there was no anime boost. Rather the drop is what you'd expect from a 32 month gap between one volume and the next in a series.

    – Using one series' success from a 10 ep series to push the idea that this is all you need is a bit odd. There's no way of knowing that this series would not have done better still if it had received more episodes. Minor point, though.

    Other than this, some interesting stuff.

    • My understanding from my cursory research of Gate as a series is that the main story concluded with the 5th volume released in 2011, all 5 main volumes were taken from material originally online, and the subsequent novels released have been collections of side-stories. I really didn’t want to get into spinoffs of any kind, though they obviously matter in the equation. That’s why as far as math goes I mentioned it was reductive, and maybe I should have just caps-bolded-italicized that I was looking at incomplete data that spoke to the minimum possible amount of sales gained. I thought I was more clear that I was being super-conservative and the KonoSuba pre-post anime case helped underscore things, but w/e.

      Wikipedia lists O;N as an ongoing serial novel, and the disk sales being disappointing I think gives enough indication it elicited little interest, I could have just as easily subbed in Heavy Object from the previous year to make very much the same point.

      Within manga, I’ve found the 2-week totals to be fairly consistent from volume to volume in the absence of some kind of outside stimulus. Also, it’s arguable that having a limited edition version of a volume doesn’t boost sales as much as it just shifts sales from the cheaper version to the most expensive version. Haganai specifically was difficult because both volumes 6 and 7 included major bonuses, I had a choice between Going back over a year to volume 5, when sales were still increasing volume by volume 40k on volume 3, 60k on v4, 90k on v5, 180k on v6 with the drama CD. A drama CD is a significant bonus, but since this went on sale way before the anime, it’s likely most people buying the Drama CD would have bought the anime. It’s obviously not a decline, but using a consistent methodology, it was tricky to find a way to count a huge positive in per-volume sales that also allows a fair comparison with other series with no long-tail data available. You’ll note I didn’t claim it as an example of a poor boost – I had a list of series with poor results and it wasn’t on there.

      You don’t have to assume I got the data from MAL, I was very clear about my sources in the article. If they were consistently incomplete, though, that’s partially on me. Particularly, I assumed they would count most regular novels as they did for Kotenbu and Another during the airing periods. N/A doesn’t mean the sales were zero, just that I couldn’t find it on the charts I was looking at. The main results I plot are from the ones with both before and after data available (only the histograms include the N/As).

      Counterfactuals such as the one you give on KonoSuba are a never-ending rabbit-hole. You could always speculate that a series would have done better ‘if X’. The fact is that KonoSuba did well in the format it actually came out in, showing that the approach works, which is going to make it look more attractive to some people.

      • I have no more info than you do as to whether or not Occultic;Nine is ongoing, but whether ongoing or not, it hasn’t had a new volume out since April 2015, so there’s no “after” volume that could have got on the rankings. With only 2 volumes out it would really have had to actually enter the weekly volume rankings (which a lot of adaptations don’t get for their sources, and which would require an even bigger boost from a 2 cours series than a 1 cour one). Heavy Object would be a much better example.

        I’d be very surprised if manga are consistant from volume to volume whether it’s out for 9 days or 13. Or for series that are borderline as to whether or not they rank twice or not, 4 days or 10. It certainly isn’t the case with light novels, though. I’m not sure there is anything you can do about this other than simply acknowledge its existence, though, and as I said, across a range of data it will even itself out.

        “You don’t have to assume I got the data from MAL, I was very clear about my sources in the article.” – Sorry. I forgot that bit by the time I was writing. MAL has cut back the number of regular novels it includes over the years. The new Kotenbu series volume was ranking regularly for a couple of months after its release. I found the sales after 2 weeks on 2ch at 38675 by the way(

        Re: counterfactuals – indeed. Which is why I said it was a minor point. You could just as easily do a comparison between NouCome and, say, Tokyo Ravens, though – and if you point out that NouCome got a bigger proportional boost, then I could point out that Re:Zero got a much bigger proportional boost than KonoSuba.

  2. Your “tapped out” observation is quite novel. I think it’s something we all suspect, but having emperical proof is assuring. The anime industry has always been ferocious in its appetite in source material, and we saw this time and time again in manga, vn, and next on the plate appears to be isekei web novels?

    • I think the trend is happening and it’s movies adapted from TV anime rather than TV anime itself that’s going to see more light in the next few years. I’d like to write about that, but sources that are consistently accurate and easy to browse are hard to come by.

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