Shang, and all of the post-dynasty collapse centuries like The Spring and Autumn Period, were not great times to live in. Dismal and evil vibes, for the most part, unless you happen to be a mighty hero or bandit-lord who believes that he can conquer the age. Even so, most of them ended up in soup pots.
Notably the Tang Dynasty in China was concurrent with the Taika Reforms, Nara period & beginning of the Heian period in Japan.
There's some truth to this. The Japanese preserved certain Tang Dynasty customs which were lost to China, and they have some of the best collections of Tang-era artifacts.
This line of thought was, however, used in very unfortunate WWII-era propaganda, like "we have to invade China to rescue its civilization, only we can do this!"
I'd argue its difficult to find major aspects of Japanese culture that don't trace back to ancient China (maybe the language, eating raw food and sumo)
[0]: https://en.wikipedia.org/wiki/Late_Shang#/media/File:Shang_d...
[1]: https://en.wikipedia.org/wiki/Rhinoceroses_in_ancient_China
Shang being an villain fits this narrative.