How would an Eastasian rank system work?
considering Eastasia is for all intent and purpose an enlarged China, it could be based on the collar insignias formaly used by the PLA:
http://www.uniforminsignia.org/?option=com_insigniasearch&Itemid=53&result=1339
I first read how Eastasia had an “Obliteration of Self” ideology, I concluded it must have been Japanese annexation of China and Korea, not the other way round. Orwell might had Kamikaze death squads in mind when he said this. (But yet, “Obliteration of Self” also reminded me of Neo-Confucian “conserving principles of the heaven and extinguishing human desire.” thing. )What about the banner system? Could that be integrated into the army?
http://www.chinaknowledge.de/History/Terms/baqi.html
Orwell wrote the book in 1948, when Japanese Empire was still not a distant memory, and China was still in chaos.
So you might want to look at IJA ranks.
But if you are looking for something more traditional, the East Asian tradition was to use coloring to denote ranks.
http://t.www.uniforminsignia.org/?option=com_insigniasearch&Itemid=53&result=3737
In Late-Qing reforms, in accordance with tradition, red was used for general officers, blue field officers , white company officers.
For myself, I was interested to see a modernized Mandarin Square system
https://en.wikipedia.org/wiki/Mandarin_square#Military