First, the term "common culture" is relative. In here they are talking about intellectual ideas. There always existed seductive ideas spreading among the (somewhat free) class of intellectuals but these shared flows of ideas were not necessarily representative for neither the (territorially divided) masses of people living somewhere on lower levels of the social ladder nor for the class of rulers above them (which were clearly territorially distinct before unification). The said scholars were in a privileged position of affording to maintain relations with outsiders without much hurdles. The underlings were too poor or too mediocre to want such things, the political lords above them were bound by loyalties and other obligations which made interacting with equals outside their political sphere difficult and suspicious. So this "common culture" may not be more common than say, revolutionary/socialist ideas shared between small groups of intellectuals across the Europe in the eighteen-nineteen centuries. Actually, "not necessarily representative" is too mildly put considering the heavy censoring that casted them into oblivion afterwards!
Second, this is a batch of documents extracted from one place. It's safe to assume that all they reflect is the views of whoever gathered them. It's the confirmation bias, you know?
> Second, this is a batch of documents extracted from one place. It's safe to assume that all they reflect is the views of whoever gathered them. It's the confirmation bias, you know?
The point though is that some of these documents went a very long way to find their burial in the south. Yeah, a sample size of 1 isn't very much to go on (maybe these documents were kept because they were prized possessions of 'foreign' lands?), but it does show in the very least a deep cultural contact between disparate kingdoms in the pre-China age.
"but it does show in the very least a deep cultural contact between disparate kingdoms in the pre-China age."
Cultural contact - yes, deep - not so convinced. If the said territories would indeed have been in a deep cultural tie they wouldn't had to be united by war. Look at the Romanian unifications:
Second, this is a batch of documents extracted from one place. It's safe to assume that all they reflect is the views of whoever gathered them. It's the confirmation bias, you know?