What is that stuff that Yelan was mumbling to herself about? We know at least about the Five Regions and the Five Gods of those regions but what about the rest of it?
Well thankfully she started it all off with Yin Yang right because that already tells us it has to do with Taoism. Specifically she's talking about the religious side of Taoism that as far as I know deals with gaining power over nature or harnessing the supernatural powers in nature. Onmyoudou and being able to summon spirits out of paper cutouts called Shikigami come from this side of Taoism.
So from what I can tell the stuff Yelan says is from Bagua and actually goes like this: 中央者,阴阳之内,四方之中,经纬通达,乃能端直,于时为四季
You guys can totally see how they're connected right? 
Ok maybe if I showed you the Chinese version of what Yelan's mumbling about: 阴阳之内，五方之中。水火风雷，循环无端。执七辰于地，三门开张，经纬通达…… (bilibili is awesome you guys haha)
Now from here we just try to match up the cool pictures. You start out with 中央者 from the Bagua but Yelan starts with the next line 阴阳之内. Those first 3 words mean one who is at the center. This is a reference to one of those Five Gods I mentioned from my first topic on Bagua. Remember how they each represented a direction? Center would be the highest position. Then the next part is how Yelan starts the line in English "Within Yin and Yang."
Then the next part is about those directions but the original had already mentioned the center direction right? So it goes 四方之中 to mean the four remaining cardinal directions 四 meaning 4. For Yelan she says 五方之中 where 五 means 5. So already we know she's divinating in Bagua using the power of the directions. That's where the "compass" would come into play.
I'm not sure if any of you guys are fans of anime. If you are you might have seen the next few words: 水火风雷. These are actually 4 of our elements in the game 水 for Hydro, 火 for Pyro, 风 for Anemo and 雷 is Electro. But to be more confusing I don't think she's even trying to reference any elements. In China they had 5 classical elements and those elements feature in Taoism too but Anemo and Electro aren't part of it. For a while I had no idea what she was talking about and if she was referring to in game elements why specify these 4? I even looked at Domain 2 that I used for my Pyro Yaksha = Pyro Archon theory and no it wouldn't work because Pyro is missing from that and that fact was even part of my theory.
No instead it's another reference to Bagua from the compass again. They use different words but still represent these elements and they pair with each other: water with fire, wind with thunder. (which doesn't come across in English) The full picture would be 天地 风雷 水火 山* but I'm not sure if Yelan talked about these 2 pairs for any specific reason. (Again the Bagua stuff goes over my head. 
)
Here's a simplified picture that lists those words with the element they represent.
Actually the full phrase she uses is 水火风雷，循环无端 and the second part is that they cycle endlessly similar to the seasons as she mentions in English. This is another aspect to this religious Taoism which is that Feng Shui changes all the time and the world itself is constantly cycling so you always need to reorient yourself to stay in line with the Tao.
Next you have 执七辰于地，三门开张，经纬通达 where it finally ends with something that the original also does 经纬通达. So what is that stuff that MiHoYo added? Well at first I was jumping out of my seat because a couple of sources said 七辰 was about the Seven Classical Planets! But just like the previous thing it's actually more Bagua. 七辰 can also just mean the stars of the Big Dipper which have been used in navigation for a very long time. But the next part does seem to have to do with Genshin thanks to another relation it shares with Taoism. The 三门 or Three Gateways are of (I think you guys know what I'm about to say) the Light, Human and Void Realms.
The point of both additions is explained by that next statement 经纬通达. 经纬 means latitude and longitude and the whole phrase means the connection of all latitudes and longitudes. It's similar to the English but not quite the focus. "all the world within reach"
The whole line means that if you can grasp the seven stars of the Big Dipper alongside the Earth (understanding Bagua's system of navigation) you will be able to open the doors to the Three Realms and connect the world together.
Finally the original Bagua saying continues on with 乃能端直,于时为四季 which is just a closing statement saying once you've done these things you will be able to correct your path in accordance with the seasons aka nature.
In our world this saying is a Taoist mantra about how to utilize the qi (or chi or ki however you would best understand it) and correct its flow in yourself so that you can then command the natural forces. In Genshin I'd actually think we have those natural forces. It'd be the Ley Lines which I've theorized about a few times now because of this quest.
I pondered last time how important this Bagua stuff would be in Genshin. Could it be another way the characters in the game can find out more about what's going on? If the Bagua stuff is actually related to the Ley Lines in MiHoYo's interpretation it just might be. 
Tips and Tricks from a Super Casual Genshin f2p
