(for chapters 1-5)
Facts:
* Political landscape inspired by the collapse of Zhou dynasty through Warring States (even Three Kingdoms) situation, the Emperor being overpowered and overshadowed by the vassal lords
* Quotations from Master Meng, Master Zhuang, Master Mo, Master Sun's Art of War, Book of Odes (or Classic of Poetry), Master Han Fei, Inner Canon of the Yellow Emperor, Master Xun, Dao De Jing, monster imagery inspired by entries in Classic of Mountains And Seas
* Zodiac hours; an ancient Chinese hour equals two modern day hours
* LGBTQ+ existence (but definitely not enough documentation, because even celebrities had to compete for attention to be documented by historians)
* examples of natural (not stage voice) but "unexpected" vocal pitch: Jamyang Dolma, Zhou Xun (actress), Zhou Shen or Charles Zhou (here he sings in an even higher pitch, here he changes his pitch higher and lower)
* traditional bowing etiquette
* proto-celadon ware
* Around that time period, at least well-to-do people might have been using "spoon" for eating rice/millet, while using "chopsticks" for cooking or to pick out vegetable/meat from either the still-hot cooking vessel or the plate (like a pair of shared-chopsticks when sharing a meal with other people). I can't be certain how "well-made" poor people's eating utensils were, or if they didn't consider the lacking of eating utensil an issue.
* 十二章纹
* Music-related: Yue Folk's Song 越人歌 (modern version: female vocal, falsetto, male vocal), seven-string zither 古琴 (started from five-string pre-Zhou, then added one and two more by Zhou dynasty; there was an excavation of a ten-string zither for Warring States period), Yu pipe 竽 (36 pipes), Chime Bells; Chime Stones, Warm Spring, White Snow
* Arts-related: ritual dancing in military context
* game of Encirclement 围棋/弈, or Weiqi/Go/Baduk, but was played on 17x17 board, not the modern day 19x19; the ancient Chinese rules vary from the modern Japanese-influenced rules: it used to be white first (or any side can be first), usually played by the stronger side, and the opening 8 moves around the corner star positions is what limits the advantage of the initiator (philosophically/symbolically it's also setting up the initial balance of power), so there was less need for the 5.5 points compensation. Based on this archaeological finding, it is plausible for Go stones to be made in Bronze, Lapis Lazuli, or even other material, as well as being not strictly black versus white in color (and they are shaped like small eggs in that video.)
* Acupuncture (but the needles of that time looked different than modern day ones)
* Medicinal ingredients: Snakesbane 蛇灭门 (Thermopsis lupinoides), Lingzhi 灵芝 (Reishi Mushroom), Dingxiang 丁香 (Intermediate Luculia), motherwort 益母草 (Leonurus japonicus), sealwort 黄精 (Polygonatum sibiricum), "wolfbane" 狼毒/断肠草 (Stellera chamaejasme)
* Weapons and Armors: Scaled Leather Tunic or lamellar armor, rattan armor 藤甲 (idea borrowed from Romance of the Three Kingdoms)
* Cultures where the population might be few and livelihood difficult to sustain, both men and women were expected and encouraged to know how to hunt and fight. Before becoming "civilized" by Confusian advocates, it is said that cultures like early Qin people (fought neighboring nomadic tribes), Zhongshan people (were nomadic themselves), Chu people (driven to the south to start over), all championed the fighting spirit for everyone in their community.
* Eyebrow-painting with charred willow branch or graphite
* hostage exchange, First Emperor of Qin was the son of someone who did go through that experience
* The significance of direction of seating, at least during Warring States period. In a square arrangement, east-facing is for one with highest status, south-facing next, north-facing after that, and west-facing last. In the Emperor's audience chamber, Emperor always sits south-facing, and favors people on his/her right side
* Earlier Eight Trigram pattern
* Inaction
* 锅盔 crusty pancake as military ration, easy to carry by individual soldiers (instead of piled up on wagons)
* Calligraphy ink cannot be wiped clean easily from basic bamboo strips (it's not like a whiteboard with specialized markers). Otherwise so much ancient text couldn't have survived till modern time. Writing on bamboo strips are usually scraped/carved off, or use orpiment (Arsenic trisulfide) like White-Out, then write on top of that layer. 战国时期砚台与墨丸
* close combat: boxing matches (战国时期“相搏”, Zuo Commentary's entry on Duke Xi, chapter 28 mentions the Duke dreamed that he was boxing another Duke), sword fight (in Zhuangzi, King of Zhao held sword-fighting matches like Rome's Gladiators)
* Cuju, kickball
* actual geological locations: Mount Tai, Yellow River, Long River
Anachronism:
* Qin Emperor's color was Black (for the Heavens/Space, or the Qin state element, Water). I'm not sure about the official color of the declining Zhou dynasty (maybe red for the Fire Element?). Not yet Yellow (a few potential reasons, such as association with the Yellow Emperor, or the association with Earth, etc.) from Sui dynasty onward (when an Emperor preferred the commoner's clothing color, but later in Tang dynasty was "legally" made into the Emperor's color). I like the imagery of black for the blackness of the universe, and also I'm thinking about the unification in the story, just like what the Qin Emperor achieved.
* Grist mill and wheat might have already existed during late Warring States period, but noodle might not have been as common.
* Ring-Pommel Blade (?) 环首刀 might be more prominent during Han dynasty
* Current archaeological finding of stir-up dates its invention after this general time period, so may fudge the exact time a bit
* The shape of the seven-string zither ("guqin") might not have stabilized at this time but at later Wei and Jin dynasty. There was also a ten-string zither from archaeological finding. They might have all been developed from a five-string zither.
* Candle was still very expensive to make around that era, so should be even less common than mentioned. Lots of bean oil lamps more likely.
* Trousers in the modern sense came into common use much much later, but Qin soldiers, prisoners or laborers wore some kind of trousers for ease of movement, and northern horse-ridding cultures had trousers that were later adopted by Zhao state military (but maybe not extended to commoners); most people just had long tunics to cover as much as possible even in a sitting pose, lower leg sock-like shoes (for aristocrats), or simpler crotch-wrapping cloths (like what Japanese Sumo wrestlers wear)
* 西周时有合裆裤？
* During Warring States period an Emperor probably doesn't have a throne-like seat, just that he has more fancy stuff around him when in his official seating position
* Rainbow Skirt and Feathered Robe (霓裳羽衣) dance is from the much later Tang dynasty; and I don't really know what the routine looks like; supposedly the music is based on or inspired by Music of Brahmin (婆罗门曲), from ancient Kucha (龟兹) region
* Gulls and Herons Forget Scheming, from the much later Song dynasty
* Not sure about when pressure points have standardized names, so I'll assume what I can find in pressure point diagrams are based on later era medical text. Actual pressure point names: Chize, Quze, Yitang, Qianquan
* There must have been female physicians, but currently the earliest historically-acknowledged one is 义姁 during West Han dynasty.
* From the later Song dynasty and onward, 圣旨 ("Imperial Edict") the term may include all types of official order from the Emperor.
* Paper is better documented to be "more easily mass-produced" during Han dynasty (after the Warring States period and Qin unification), because there may have been recent discovery of pieces of "proto-paper" that survived the elements (earlier Western Han dynasty also had paper, which scientists speculated their use to be more likely as wrapping material before they are more widely used for documentation). I also believe animal skin type parchment may have been possible, just rarer, and not really common among people who don't read/write.
Fiction (some plausible hand-waving):
* The Stems-and-Branches system 60-year-cycle simplified by me into an Elements-and-Zodiac system 60-year-cycle (because I didn't memorize the Stems-and-Branches terms, but I know the Elements and the Zodiac order)
* Zodiac-associated months (apparently there are associations, but the date ranges do not correspond to the dates of each modern month as cleanly as I would like in the story for simplicity)
* I'm not sure swords at that era consistently had scabbards. The swords/blades as burial offerings I saw did not have them, and generally they were not displayed in museums with an accompanied scabbard. Maybe the wooden scabbards all rotted to nothing by the time they were unearthed, since there were bronze swords that had bronze scabbards. Regardless, I want the imagery of unsheathing, so I gave them all scabbards.
* Fighting with Qi (Qi energy is not fiction, but in this story I'm too loose with its depiction, going with the Wuxia flavor)
* wuxia-inspired martial arts should look and feel more "primitive" at the time; I can't find definitive argument of whether India's Kalaripayattu is a major influence to much of later era martial arts or not, only certain that "native born" martial arts would definitely have existed and evolved (every closed community in the world would develop its own fighting style), examples were stories of the assassins during the Warring States period, Swordswoman of Yue, Master Zhuang persuading King of Zhao to abandon his obsession with watching swordsmen kill each other, etc. True martial arts were born out of the necessity to kill. Fight in a way to not get killed, not about looking cool while doing it.
* Wester Corridor is based on Hexi Corridor, the exact going-ons during that period will be glossed over or fabricated in service of the story, but it will still symbolize the spirit of the Silk Road (which more officially began during later Han dynasty). Commerce between tribes of people have always happened at local levels. So there may have been a similar "Stone Road" during the Stone Age, and a "Bronze Road" (see Ordos bronze ware) during the Bronze Age, etc. Exchanging crafted ware and crafting techniques. The region may have also been less arid than we know of today (or maybe I misread some information; documentaries have been able to provide a less desert-like scenery, however, so I don't know just how desert-like it was at that era).
* Heaven's Ritual in the story is a mashup of actual Heaven Worship (done in winter season) and modern day Spring Festival, because I don't want to write around too many distinct festivities; and the specifics that happen during the ritual are not thoroughly researched, only sprinklings of the general idea, such as ritual dancing, distribution of sacrificial meat based on status and level of contribution to society/community, etc.
Fiction (total BS):
* Ancient Chinese does not sound nor look like modern Mandarin (ignoring the fact that it then has to be localized for each specific readership), especially when it didn't go through something like the Qin dynasty standardization
* 99% of location names and character names (besides existing authors of writing that were referenced) are made up (Google-fu will fail you this time). Most of the surnames were inspired by surnames of that approximate era, but otherwise just going by what sounded reasonable. I try to avoid overlaps, because pinyin without tone marker will make many names look the same even if they sound different in Mandarin.
* Blood-letting to cure Krait-bite? The patient was super lucky.
* BS martial arts move to knock people out with strikes around the neck region. I don't really know how that works.