So, you are saying that the "japanese vampire" variants I have seen across the internet and in comics are a recent invention due to western influence?
Be that as it may, vampires are sapient and their only mental change is the blood hunger, so I see no reason at all for vampires to not migrate to japan occasionally over the years due to lack of anyone actively stopping them from doing so.
So, we should either have the occasional western vampires hiding in japan, or the vampires could have picked up local influences and became their own unique thing.
... unless maybe the local monsters fight them for territory effectively? or maybe the kami? it would require investigating.