Early (e.g. within two generations of the end of HSDS)
Middle (e.g. equidistant from the eras of HSDS and SSwRB/DOMD
Late (e.g. within two generations of SSwRB/DOMD)
Cover illustration from book indicates Qing Dynasty too:
https://en.wikipedia.org/wiki/A_Deadly_Secret
How powerful/weak are the martial arts in the story? If its Qing Dynasty, the martial arts should be notably weaker.