one, chu kingdom was known for its practice of shamanism, which was strictly 'un-chinese-like'. none of the other proper 'chinese' kingdoms at this time did so. since hmong people practice one of the oldest forms of shamanism in china, the connection is there.
I have to say that the answer may be more complicated than most people may think. Han culture is pretty unique considering its geological location - it is surrounded by Shamanic people. Han culture inherits Zhou and Shang, so is it possible Shamanism is part of them in their very early stage?
The core of Shang culture is its worship of Tian and dead Shang kings. As the character of Tian indicates, Tian 天 is the ultimate, human looking god. As the descendent of this ultimate god, the living Shang king rules his kingdom. In other words, a Shang king is a semi god king. Quite similar to Moses of Jews. This is the correct meaning of Tianzi, or 天子．The Japanese introduced the 'Son of heaven' as its English translation, and that misinterprets Tian.
According to Shang culture, a Shang king dies and becomes an assistant of Tian, or Angel if you will. These angels protect Shang royal families and their kingdom.
Zhou people took over Shang heritage and changed the interpretation. In Zhou's version, all the ancestors of all of us, will protect their descendents. That is a great innovation toward a universal belief. Ancestor worship therefore becomes a Chinese tradition, and not just Shang tradition or Zhou tradition. And this worship differentiates itself from any other traditions all over the world.
In Chinese civilization, Heaven is never a big part of their belief. If they did, there should be a lot of descriptions of the heaven and what are there, etc. No.
And they don't worship Sky.
They worship Tian at Tiantan 天坛, but very few know that Tian is a god. Tiantan is simply (mis-) translated as the Temple of Heaven.
Again, this is not mainstream, text book history. You either agree with me, or don't agree with me.
Although Shamanism is popular in Northeastern Asia, including Manchu, Turkic, Mongol, Korea, Hmong, (and Maya in South America), Shamanism doesn't seem to exist in present-day Han culture. How can this be possible? I mean, geologically, this is the region that Shaman prevails, right?
Is it possible that Shamanism existed only in the very early stage of Shang culture, or maybe Xia culture? Shamanism is aboriginal proto-religion, but obviously not everybody gets it. Europeans don't. So maybe Han people simply didn't get it?
The First Emperor of China burnt a lot of archives that were deemed to be politically incorrect. And Confucius himself is praised for his no-comment attitude toward ghosts and super natural powers (子不语怪力乱神). What exactly were those that Confucius declined to comment on? What were lost in the burning are probably lost forever, leaving us guessing around.
However, King Wen of Zhou, who lived as an ambassador and hostage to Shang, recorded Shang rituals in a book called Yi Jing, or the Book of Changes. This book appears to be very Shamanish, or Shamanic, if not Shamanistic.
The oracle bones from Zhou are very Shamanic too.
I tend to think that Chinese culture, as descendent of Shang and Zhou, had Shamanish in its far origin and dropped its forms and practices in its very early stage. Or maybe I should say, Chinese culture shared the same origin with other (more developed) versions of Shamanism, but went a different way in its early stage.
A good guess is, Shang was shamanic in nature. Zhou changed it's trajectory. And after that, China had gone a different way.