@Archomp
Family registers in China are very in-depth.
My family has 3 physical copies, 2 kept at two separate temples in Taiwan, one in Philippines. I was given the generational name "King" (pronounced ching) that identified the specific generation I belong to. My daughter and son received "Ing" identifying theirs, however given that this is an old practice, and that access to the family registers are tightly controlled, my children may be the last ones of my family to receive generational names from the family register.
I can only assume Japan's is of a similar nature, since they used to be all "COPY CHINA'S HOMEWORK" before going "WE AHR NUMBAH WAN"