Ancient Chinese believed in the Cycle of the Five Elements idea: the elements are Wood (Green/East), Fire (Red/South), Earth (Yellow/Center), Metal (White/West), Water (Black/North). All Five Elements are in constant move, and pass through cyclical changes (phases). The main cycles are the Generating cycle and the Destructing cycle.



The Generating Cycle: one element (serving as parent) strengthens and promotes growth of the next element (serving as child): Wood feeds Fire -> Fire creates Earth (ash) -> Earth bears Metal -> Metal collects Water -> Water nourishes Wood:

The Destructing cycle is when one element suppresses another element: Wood breaks the ground (Earth) -> Earth soaks up Water -> Water puts out Fire -> Fire melts Metal -> Metal chops Wood:

(There is also the Weakening cycle, which is basically the Destructing cycle in reverse order: Earth can bury Wood -> Water washes away Earth -> Fire evaporates Water, etc.)

Because of this belief, each dynasty was associated with one of the elements of the Generating cycle. Therefore flags and formal dress of each dynasty were colored according to the dynasty’s element: Green for Wood, Red for Fire, Yellow for Earth, White for Metal, Black for Water.



The official color could be changed during one dynasty’s rule: the Han empire went from Black (Water; inherited from Qin) to Yellow (Earth) in 104 BCE, then to Red (Fire) in 27CE. But this applied only to the color of the flag: the official dress color of Han always remained Black.



The official color of the Wei empire was Yellow, and its element - Earth, according to the Generating Cycle, since Wei succeeded Han. (I believe Wei, like Han, also retained Black as its official dress color, that’s why sometimes Wei colors are said to be Yellow and Black: Yellow flags, Black formal clothes.)

The official color of Shu was Red, since Shu proclaimed itself the continuation of Han, not a new dynasty/empire, and so adopted Han’s color and element.

The official color of Wu was Green. Wu positioned itself as a new state completely unrelated to the Han empire. So the people of the South “reset” the Cycle and chose its first element. By doing this they demonstrated their independence from the North.

Jin had Red official color, despite its Cycle element being Metal (White): it was postulated (by Fu Xuan) that the official color should only be changed if a dynasty was destroyed as a result of a war. Since the transition from Han to Wei to Jin was peaceful, the official color was “reset” to that of Han. After Jin, this became customary.

So, historically, the colors of the Three Kingdoms + Jin were the following:

Wei - Yellow (Black for official dress)

Shu - Red (and probably Black official dress as well)

Wu - Green

Jin - Red

Chinese card game Sanguosha more or less follows the historical tradition:

Wei - Blue

Shu - Red

Wu - Green

In Dynasty Warriors the colors are different:

Wei - Blue

Shu - Green

Wu - Red

Jin - Light Blue

As for Wei being Blue in both games: from the design point of view, when you have a lot of very diverse characters, Black isn’t the best choice: it lacks shades. Since Dark Blue can also sometimes serve as the color of the Water element, in both games Blue substitutes Black. Both Dark Blue and Black also symbolize North, and that’s where Wei is.



It’s interesting that both games avoid using Yellow for Wei. Probably in order not to confuse Wei with the Yellow Turban rebels. (Or because Yellow has a strong association with the legitimate imperial power.)



So why did Koei switch colors for Wu and Shu? Actually, I think when Koei started to design factions in DW they didn’t even think about the official colors of Chinese dynasties, and chose color scheme based on directions: Red is the color of South, so that’s Wu, Blue is the color of North, so that’s Wei. According to this logic Shu should have been White (being in the West). But White is as difficult to use in design as Black, besides Koei needed a bright and contrasting color, so they settled on Green, which has a lot of positive connotations and is suitable for the “hero“ faction.

For Jin color scheme Koei found (intentionally or not) a perfect solution: they understandably couldn’t use Red, so they took Light Blue as a way to mark Jin as the successor to Wei, and added a lot of White which historically was the color of Jin’s Cycle element - Metal.

A nice article that lists Chinese dynasties colors and talks a bit about color significance in Chinese culture:

http://eap.ee/public/trames_pdf/2012/issue_3/Trames-2012-3-237-285.pdf

