History Sengoku Era "Nationalities"

[Michealin]

I have an AU in which Japan is still locked in the Sengoku era. Currently, there are only six known* characters; Koyama Ryuu, Koyama Akemi (mum), Koyama Toshio (dad), Ryuu's two sisters, and Tajiri. While Ryuu lives in a modern Japan-equivalent, she still identifies as more from her home reality and clan then from Japan. What's the proper "nationality" of someone from pre-unification Japan?

* several more presumed from Ryuu's bio

..."[ S ]he didn’t decide to become a shinobi until she and her father returned from visiting the smith Tajiri to find her mother and sisters dead. A few days later, the Koyamas returned to Tajiri’s forge and commissioned Ryuu’s first pair of sai from her. Thus, they resumed their family’s patronage of the smith’s family"....

 

[thomas]

I’d say that Japanese in pre-Meiji Japan owed fealty to feudal lords (daimyō) and after the establishment of the Tokugawa shogunate - as claimed in the link below - to the shōgun and (by extension) to the emperor as well. You could probably claim that they were “citizens” of their local domain (藩, han).

Until the Meiji Restoration, Japanese people were subject to both the local authority of the daimyō and the national authority of the Tokugawa shogunate, who pledged allegiance to the Emperor. A concrete example of the shōgun acting directly on Japanese people as a nationality would be blanket recall of Japanese people from all other nations during the sakoku period, which resulted in the end of communities like Nihonmachi in Vietnam.

History of Japanese nationality - Wikipedia

en.m.wikipedia.org