My understanding is that it is based on the specific contract.. I know the 737 guys at ANA are based there, so I assume they have to have the right to live there.. My contract position is a commuting one, and does not allow me to live there.. I have no desire to live there fulltime, so this suits me..
I am by no means an expert.. My first experience with a Japanese carrier..
Hope it helps.. There is a fair amount of chatter on prune in the Asia thread about a lot of this too...
EKBC