I'll read more into it. I just don't know if readers wpuld accept my fictional made up settingNo. It has been done many, many times. Read Guy Kay Gavriel for examples of how to do this well.
The Qin was from 221BC-206BC and the Yayoi period from 300BC-250AD so they could of crossed paths when the emperor went to Japanwas struck by the statement about Yuyai and Qin being contemporaneous. That's the sort of thing an author should know if they're going to write about the period.
So how do I make up an Asian country with Chinese influence, without seeming like it's disrespectful? Where do I get inspiration for making a made up Asian nationality? Sake for Japanese influenced countryyou gotta do your research. I'm talking hundreds of hours. You can write the story without doing that research, but you already have a sense that you're on some potentially difficult ground. Failing to do the research simply makes the ground more filled with pitfalls.