Even if you are the type of person who can accept the existence of spirits, you might find it very difficult to accept that the entities within Touhou could be real spirits. This is because they do not fit into cultural expectations about what spirits should look like. Or rather, their given – or chosen – representations do not fit our expectations. I assure you, they don't really look like anime girls. I'm not sure if they ”really” ”look” like anything we could comprehend. Things looking like something might just be a construction of beings with optic nerves, ie. us. But they are most definitely capable of choosing different ways to manifest themselves.
The habit of dismissing spirit manifestations that are too ”weird” or ”silly” has plagued both paranormal research and spirituality about as long as both have existed. Yet there are countless examples of spirits choosing to manifest in surprising ways. A cursory glance at the literature surrounding encounters with ”high strangeness”, as spirit manifestations that do not conform to cultural norms tend to get called, will reveal some absolutely baffling entities and behaviours. The history of spirituality is also filled with extremely bizarre entities. The only reason certain types of biblical angels are accepted as genuine entities in certain religious and magical circles is that they are so well culturally established. If such tradition did not exist, any encounter with a wheel of eyes or a sphere of wings would get filed under ”high strangeness”.
Why would they want to be seen like that?
Spirits appearing something akin to an ”anime girl” isn't even all that unheard of. When Greg & Dana Newkirk chuckle at UFO contactee art looking ”just like anime” at their podcast, they are more right than they would ever suspect that they are. There are indeed a ton of reports with contacts of entities that look like humans, but have very large eyes, underdeveloped chins and noses and very thin or no lips. The extreme end of this are of course the ”gray aliens”, but there exist substantially more human-like variants of these encounters.
In particular, the golden era of UFO contactees produced great many reports of ”venusians” or ”nordic aliens” visiting people. Sometimes they were indistinguishable from humans, sometimes they indeed had features that remind one of anime characters. Sometimes they were described as being very attractive, sometimes to the point that witnesses would develop an erotic obsession. Reports of these kind of human-like entities persist to this very day.
A worthwhile sidenote here is that there is an example from Japanese culture that plays with the similarities between anime girls and popular depictions of aliens. In the profoundly souled and downright gnostic Serial Experiments Lain, the titular main character Lain at one point encounters a gray alien entity which is, puzzlingly, wearing a green and red shirt. Later on in the show, another character sees Lain, but she has the body of the alien while retaining her own head. Considering how the series implies that the internet was built using alien technology and that Lain is some kind of a deity that has been made manifest via the internet, there is a lot to unpack here.
Not all almost-but-not-quite-human encounters get conceptualized (or perhaps presented) in an ”alien” context. There are reports of people encountering ”faeries” or ”gnomes” or entities they fail to categorize that are human-like but have unnaturally large eyes and other ”anime”-like features. It should also be noted that ZUN's art is definitively on the uncannier side of anime-style art, and I mean that in a good way. I think he is doing his best to capture what he sees with his mind's eye. I don't think I'm alone, considering how many people say his art is ”souled”. If people only knew how ”souled” it really is..!
Why so many spirits manifest with big eyes, small chins and noses and weak lips is an interesting question. As it is unknown how much of the process of perceiving them is projections and how much is perception the question is very hard to answer. It might be a way for the human cognitive apparatus to attempt to piece together something that wishes to make itself known in a way that we can kind-of but not quite identify with. A spirit might be trying to essentially communicate ”I am not like you but I want you to be able to relate to me”. The big eyes might come from an understanding that they in a way possess superhuman perception, the reduced nose, chin and mouth might communicate that they do not need air or food as we do and that they do not communicate like we do.
If the spirits themselves choose this appearance, it might be a more intentional way to communicate such things. If it's intentional projection, one can imagine many reasons why they would choose to appear in a way that is seen as pretty, beautiful, cute or even attractive to some. These reasons can range from wanting to present themselves as relatable but not too human to wanting to present themselves as something we can give our energies to. Such motives would vary on a case by case basis.
I was planning on making a collage comparing ZUNart with certain depictions of alleged aliens and fae.
Sadly the enshittification of search engines has delayed this task.
I really should have saved and hard copied everything even tangentially interesting into multiple sources.
Have a placeholder Heian Alien.
OK, but why are they all girls?
The 2nd half of ”but they're anime girls” is of course ”girls”. The conventional answers to why all Touhou characters are female is that ZUN is an otaku pig who wanted to create a fantasy world where there were no other guys to interfere with his fantasies and other otaku pigs ate his slop up. This is a gross view and a gross simplification. First of all, there are male Touhou characters. Most of them play rather minor roles in the print works, but they are there.
Secondly, I have every reason to believe that the idea of gender gets very abstract with spirits. Nearly all spiritual traditions see some kind of masculine and feminine energies existing, but many also hold that for example humans, human souls, human spirits, essentially have both and simply just materially manifest in ways that fit (mostly) either of these categories. There are many Touhou characters who look like women, but have quite masculine energies. There might be an element of projection and/or creative interpretation going on. ZUN initially considered making the historical Myoren as a man the last boss of UFO, but by that time Touhou was so established to have a female cast in all important roles that ZUN thought it was weird. This of course leaves the possibility that the spirit of historical Myoren was manifesting itself through ZUN...
Another element that possibly contributes to this is that historically women were in many important spiritual roles in Japan. Amaterasu Omikami is the head of the pantheon of heavenly kami. The early empressess were thought to have immense spiritual power and at some point this also translated to political power. Until the Meiji era when such was banned as ”superstition” the miko would perform spirit channeling, and not even the ban managed to stamp this tradition out completely. The idea that spiritually powerful beings are female can be found all over the world, but perhaps this is a bit more pronounced in Japan than in some other cultures. Thus the spirits might consciously choose to manifest as such, or be subconsciously interpreted so.
There exists a concept of the divine feminine that is found in certain traditions. Within there it's thought that there exists a divine masculine world of ideas and the divine feminine world that is more closely aligned with the material world. Hence we tend to speak of things like ”mother Earth”. Taoism has its famous division of yin and yang, where yin is the feminine principle. But the Tao itself is also spoken of in feminine terms, even if it's not gendered. If a substantial part of the spiritual ecology of Touhou would be something that is bound to real locations, then it might very well manifest in ways perceived as feminine for that reason too.
Overall, the idea of various deities and spirits changing their appearance and name while retaining their core essence is an idea found all over the world, save the monotheistic religions. The bodhisattva Kannon was originally a male deity from India, yet along the way to Japan he changed gender and name. Inari Okami has been variously depicted both as a man and a woman. Even Jesus Christ was at times depicted in an almost androgynous way to underpin his merciful, gentle nature. It might just be that certain deities or spirits looking a certain way or being of a certain gender might be just another human projection.