The skill of knowing not only the social norms of your own Kinship and how to navigate them, but knowing what is and isn't proper across all five, very different societies.
0: You can follow along at dinner well enough.
1: You know that the forks are on the left and the spoons on the right and just about every other custom known to having a pleasant dinner.
2: You know that greeting a Thalerith with meekness will likely see you laughed at.
3: You tend to know titles of all the Kinships and use them with out stumbling.
4: You even know the nicknames of all the Kinship leaders, and when it is appropriate to use them, or not.
5: Without doubt, you understand the consequences of your actions wherever you are.
6: You know not only the history of each Kinship, but you understand how those actions changed and shaped their cultures.