I have heard that here is a group of people in Japan who are basically treated like the untouchables of India. They are called the Burakumin. These people have ancestors who worked in various trades regarded as "unclean".
You are correct. They are also referred to as "Eta". I believe that their ancestors were the butchers and tanners. Even today, you will find that many leather dealers are Burakumin. Intermarriage with "racially pure" Japanese is a cultural "no-no" and close examination of the ancestry of a prospective bride or groom is done to make sure that there are no Eta ancestors.