Yuuki Yuuna is a Hero is a story notable for several reasons, one of them being its portrayal of a semi-theocratic society. We are shown hints of the setting’s god-tree religion affecting the education system and government, and obviously religious undertones would make into the everyday lives of ordinary households and leave a mark on the naming patterns of children. In fact, every character in the show bears some mark of this religious influence.
Starting from the Washio generation:
Tougou Mimori’s name means simply "beautiful forest".
Minowa Gin’s name means "silver", which is formed with the "metal" and "root" radicals. The "root" reference probably doubles as an indication of Gin’s role in the group as the one keeping the other two safe.
Nogi Sonoko’s name refers to a "garden", which is most understandable if you imagine Japan’s extensive shrine and temple gardens. As a sacred space, the gardens create a small world to house the Japanese gods. On the one hand, this represents the inner sanctum that the Nogi family, as one of the most influential Taisha families, is responsible for. On the other hand, the Shikoku barrier can be seen as a miniature garden – a place of purity cut away from the impurity (death and destruction) of the world outside. In this sense, Sonoko’s name represents all the beauty left in the world as well as humanity’s hope.
During her time spent with the Washio family Mimori’s name was changed to Sumi. It is a special name insofar as it makes sense for it to be given with a clear cut purpose in mind. If you ignore the kanji and just look at the reading, the name refers to "purity", hinting at Mimori’s role as a miko/shrine maiden to the god-tree. As regards the kanji, the "su" part once more refers to Mimori’s "duty", while the "mi" part signifying beauty is borrowed from her original name.
For the younger generation.
Inubouzaki Itsuki’s name is the "great tree" straight out of the god-tree compound.
Miyoshi Karin has the "two-branch tree" radical slipped into the second kanji of her name, "rin", meaning "elegant, of stern or highly composed demeanor". Interestingly, that is the older variant of the kanji, with the newer one having a "shrine" radical in place of the "two-branch tree".
Yuuki Yuuna’s name seems to have no trees in it at first glance, but that is because the upper part of the "na" kanji was simplified along the way. With the kanji originally composed of a "tree" over a "shrine", the original meaning was that of a "fruit offered to the gods". The fruit in question was offered when seeking guidance from the heavens, so the kanji also meant *what should be done?". With the two "yuu" kanji in her name referring to "bringing people together" and "friendship" respectively, Yuuna seems to ask the question and provide the answer all in one.
Inubouzaki Fuu is a mystery to me. If you dig far enough back, the kanji for "fuu" seems to have originated from the same inscription as the 鳳 kanji referring to the divine bird (phoenix), which was considered a messenger from the gods. The contemporary form of the kanji replaces the "bird" radical inside for what is now most often known as the "bug" radical, which in this case represents reptiles; as beliefs changed, people came to believe it were dragons, rather than birds, that lived in the skies and controlled the winds.
But a "fuu" name could have contained a god or tree reference much more easily just by sticking a "tree" radical to the "wind" kanji discussed above to get the "maple" kanji 楓 – the reading can stay as-is. Whether this was intentionally avoided (to point to Fuu as the one least loyal to Taisha, especially towards the end of the story?), or whether there was some other reasoning for this particular name/writing, I cannot be sure.
The last names in Yuyuyu also matter, especially with the Washio generation. Other than the Nogi last name meaning “of the tree”, making them the obvious big-shots in this world, there are many significant real-world references packed in there:
- Mimori likes being called by her last name, Tougou, because it tickles her history-otaku and nationalist fancy. She happens to share her last name with the famous Japanese admiral Tougou Heihachirou.
- Sonoko shares her last name with Nogi Maresuke, a famous Japanese general
- The above two lived in the same times, known as the “Nogi of the land and Tougou of the sea”, and were acquainted with each other… whether the two got along is a different matter
- When general Nogi died, he was deified as a god of war (and education and marital affairs) and a shrine was built for him… partly for the purposes of the Japanese army’s propaganda
- The above happened when Tougou was still alive, and Tougou was appalled to hear that the navy planned to do the same to him to regain the balance of power between the land forces and the navy. He strongly expressed his objection to the idea… but was deified anyway after his death (there are three shrines bearing his name)
Readers can probably see how the above parallels the story of Yuyuyu with Mimori learning that Sonoko was turned into a god for the Taisha’s benefit, only to be set on the same track against her will. Yuyuyu questions whether in creating heroes, we are not taking advantage of people for our own benefit.
Minowa Gin’s short, one kanji name gives off a somewhat boyish image.
I particularly like the usage of the “ko” ending in Sonoko’s name. In contemporary usage, the “ko” ending for female names ended up being so popular that around 1960, almost all women had names ending that way. That in itself became so clichéd that now parents often actively avoid adding “ko” to names. For this reason, the “ko” ending in anime is perfect to create “average Jane” background characters.
However, historically, the “ko” ending was reserved only for females of the highest social class, holding offices at court and in administration. The later popularity of the name came exactly because the “commoners” envied the image of sophistication and prosperity the ending carried.
With Yuyuyu bringing back social elements of Japan’s past, Sonoko’s name carries with it the elegance and dignity of the well-bred part of society.