What is the role of had the Chinese not come in this sentence? What is the relationship of the second half of this sentence to the first?
The significance of decorations on Chinese pottery may have remained clear had the Chinese not come under foreign influence.
Cambridge Online Dictionaries offers the following explanation:
Had you (Had with inversion)
In formal situations, we can use had + subject + verb instead of if in third conditional sentences:
Had I known you were waiting outside, I would have invited you to come in. (If I had known you were waiting outside …)
Had Margaret realised she would be travelling alone, she would never
So, in your sentence above, just replace the "had the Chinese not come" with "if the Chinese hadn't come."
