The Twelve Kingdoms/WMG

The Twelve Kingdoms is not really a land in another dimension, but a really small place between China, Japan, and Taiwan.
And by small, we mean by scale; this place hadn't have their magic disappear because it'd mean they'd be outright killed in doing so. Tiny people, anyone?
 * Just curious, where does Taiwan fit into all of this?
 * I think the first troper meant Korea...? It's closer to the China-Japan area, after all.

Human!Rakushun and Youko got a little bit too involved
in that last night before battle. Well, it'd solve all the UST they were building since he revealed his human shape. Also, even if they continued to be friends, they preferred to not really tell anything beyond the main subject resolution point, due to social constraints (and, you know, she'd be squicked to remember that he had a cute, fluffy animal shape).

== Yoko and her two classmates (make that all Kankyaku) represent immigration to Japan. Just think about it: The seemingly alien language, the difference in appearance, the strange customs, the somehow familiar society. And what's the first question they ask upon reaching meeting the inhabitants? It is, both in series and novels: "Is this China?" ==
 * Well I would say they represent Fish Out of Water anywhere. It just happened to be the only series that dealt with another world having it's own language.

Time flows with a different speed/direction in the Twelve Kingdoms compared to this world.

 * The book and Anime disprove this, time is shown to flow at the same rate by the visions of Yoko's parents. Also Yoko and Taiki are the same age, (as proved by them being in the same year at school) Taiki comes to the kingdoms at 10 and Yoko arrives 6 years later as the 16 year old queen of kei.
 * The visions of Yoko's parent probably is not a reliable source, the visions might just be hallucinations fabricated by the Monkey-Sword. But that aside, new evidence have surfaced pointing to the fact that the time flows are (probably) parallel.
 * Enki visits Earth about once a year. You'd think he'd have noticed. And he and Shouryuu are 500 years old, and from Japan of 500 years ago.

All the absent technology (and more) don't really exist because it's all replaced by magic.
It's not shown as extensively as it should, but who in the royalties needs a telephone when they have a hyperspeed youma in the King/Queen's service to pass the important messages?
 * Youma? Make that carrier pigeons... with telepathic powers!
 * Or a telepathic parrot, like in the anime.
 * This is explicitly Handwaved in the first book by a Kaikaku in En. He said that the kingdoms lack high technology because they lack the basic raw materials to create it. No coal for the furnaces means no steam power, no oil reserves means no plastic, no uranium or even magnetic ores for power production. It is even stated that like people ores and materials come from springs (Tai is mentioned to have a gold spring for example) by not including a spring that creates a necessary material the technology of the world is held back (Presumably by the Dowager of the west or the king of heaven)

Rokuta is related to David Bowie.
Well, his hair does look like the one Bowie sported while playing Jareth, in Labyrinth. It can't be a coincidence.

The Twelve Kingdoms is one of four dimensions, the other three being Hourai (our world), Konron and Kan. The shoku are an ancient and partly forgotten way of inter-dimensional travel.

 * It's what they implied in the novels, but it was too lightly implied to know if it was actually true.

Youko literally passed through Hell; the Twelve Kingdoms is the Afterlife, and kaikyaku are people that are sent off prematurely and disappear in the living world.
If you read the novels, you'll agree completely with my reasoning. She was sent prematurely to there because the youkais sent by the corrupt King of Kou invaded the living world and were trying to reap the girl for her to not be queen while the man was still alive, as reincarnation would still take a while. Keiki saved her because, somehow or another, she never reincarnated in the right time, to start with it; she probably was killed by another human, or committed suicide while she was at the Twelve Kingdoms. Then, after they had to depart, Youko passed through the same things someone in Hell would pass, until a humble and pure spirit, Rakushun, saved her, and brought her a new hope. After all kinds of endurances, she finally could be the queen of one of the Twelve Kingdoms. People at the Twelve Kingdoms can't appear to humans at the living world, as it would cause a disrupt in the balance, and bring many tragedies to both worlds, even more if they are the kings. The fact that humans can't properly reproduce, but wait nine months for the Riboku Tree to give a child might be one more indication. Kaikyaku can't learn the language because they went prematurely to the place, without dying before. Such vision would give an interesting aspect to the series, and an even more interesting interaction with some others as well.
 * Makes a weird kind of sense. In the novels, Youko has visions of the happenings back in Japan, where the police has launched a murder investigation with her as the victim...
 * And if you get far enough in the novels you find out anyone from the Twelve Kingdoms who isn't a taika would appear like a ghost if they went to Hourai.
 * Kaikyaku can learn the language though, like the scholar in En. It's just hard, and we got exposed to two lame kaikyaku (one in Kou, and Suzu.) Possibly the natives have no concept of having to teach language to adults, since they all seem to speak the same language.

The Twelve Kingdoms are in another planet, and what people there heard about other lands were just kaikyaku's imaginations.
No normal human beings should be born from eggs that pop from a tree. Their transportation to Earth is done through sea instead of sky only because their sky is partly sea.
 * So you mean the Pacific Ocean works like a big huge teleportation gateway?
 * Yes, I mean that. Their "technology" only allowed to teleport through water, instead of teleporting through air or space.
 * Not sure i would call it Technology anyway, more like Sufficiently Advanced Magic

Youko is in a coma, and everything is her hallucination.
She started imagining it after she knew a pretty delinquent that wanted her, and the region was caught by a tornado. Everything she sees and passes are hallucinations, as she's dying slowly. Ironically, one of the only survivors was Sugimoto, that was visiting her everyday and telling stuff from the real world, until she stopped doing so, because she lost her hope (and, if we go by the novels, probably killed herself); Youko possibly managed to catch that bit of info, somehow or another, as the monkey spirit talking in her sword. If we take the anime version, Asano could be visiting her as well, and telling mystery stories.
 * Or hey, wait, what if Yoko is hooked up to this giant machine, like a human battery, and this machine emulates the world of the Twelve Kingdoms straight into her mind!
 * Oooh and the Kirin are Agents!
 * They are performing Inception on her.

The Twelve Kingdoms are located in a man-made world.
Just look at the world map. There's almost no probability of such symmetrical shapes being a product of natural land formation.
 * It's a god-made world, but the god could be anyone (including human, if you want). Their legends, or at least in the Mount where the kirin grow, explicitly say the main god destroyed the world and made it anew in the shape it currently has. The thing is: it's definitely artificially made to look like it does.

Rakushun suspected who Youko was all along, and initially only helped her in hopes of getting a reward.

 * When she first meets him, she mentions Keiki's name briefly -- since there are very, very few reasons Keiki would be in her world, Rakushun would have been smart enough to, in theory, hazard a guess at her identity solely from that.
 * Also, it's possible he recognized her sword, which was one of the legendary treasures of Kei and can only be wielded by its Empress. Its powers are extremely distinctive.
 * On top of that, the fact that she was capable of speaking the local language would have given a hint to the fact that she was an immortal; there's only so many ways someone from another world could unknowingly become an immortal right after meeting Keiki.
 * He was also the one who brought Keiki up when she was talking to the scholar in the scene where her identity finally comes out -- Youko was about to leave when Rakushun 'suddenly' reminds her that she met Keiki, and presses her on what happened. He might not have known specifically or with any certainty until he heard her response, but he had more than enough reason to suspect it.
 * This would also explain why he was so willing to suddenly drop his entire life to travel with her (even if he was planning on going eventually like he said, it's still a bit shocking), and it would explain why he went to such extremes to try and meet up with her again back in En.
 * Most tellingly of all, he almost admits this himself, though not to Youko. Pay very, very close attention to what Rakushun says to Shoukei in Episode 31 while recapping his adventures with Youko -- in a blink-and-you-miss-it moment, he says that at first he thought he'd get a reward for bringing her to En, and only changed his mind as he spent time with her. It's possible that he was talking about the brief time after he knew who she was, but the way he says it leaves it ambiguous.

The Deities created the 12 Kingdoms after abandoning Earth to its own devices

 * The 12 Kingdoms humans have sex, but they serve no biological function. Further, the Tree Birthing system means evolutionary mechanisms of Natural Selection does not EXIST. Every life form in that world are individually crafted by divine forces.
 * The issue is, WHY? Why so much resemblance to Earth in human appearance, animal equivalence, and cultural resemblance to ancient China? Why does chickens in that world lay eggs for no other reason than for the eggs to be eaten by humans? A complex theory could be that Earth was created first. The Deities concerned created Earth with Natural Selection, and life evolved on its own with minimal divine input. However, at some point the Deities decided they would like to have a world where they could have direct influence. Instead of wrecking the balance of Earth which was going along just fine, they created an entirely separate universe of 12 Kingdoms. They also likely used Ancient China as the basis of the culture in the new world, as it was the most advanced human civilization at THAT point in history. The Tree system was created to replace Natural Selection, ensuring that the population was under direct divine control. However everything that could be copied from Earth was copied.
 * In short, Earth is like an ocean where life was left alone, while 12 Kingdoms is an Aquarium where the gods gets to control who goes in, who goes out, and what happens within. That is why it is culturally static; the gods wanted it that way.
 * It also explains why the gods have power even over people who escaped to Earth; the gods always have power over Earthlings, they just choose not to interfere. But people who escaped to Earth are fair game.