Well, they’d think of you as a nikkei.
The Japanese have been critizised for being more tolerant about immigrants who have “Japanese ancestry”, rather immigrants from other bakgrounds. That idea may stem from back in the 80s, when Japan started encouraging nikkei to come to Japan when they had a shortage of labourers.
But it wasn’t about tolerance really, because once the recession kicked in, the government acually offered money to immigrant nikkei to leave again. They just wanted cheap workers for a while and thought “might as well get the ones who may have an inkling of Japananese culture in them.”