What about a case like this:
A man born in the US but is also granted Japanese citizenship by virtue of his fathers nationality. His given name is different but his family name is the same in both systems. This man considers both his given names a nickname of sorts, to be used in the outside world, and his common family name to be a relic of imperial Japan (i.e. Imperial Japan would force their colonial subjects to take on Japanese family names) and kept for simplicity but his REAL name, real by virtue of the fact that this is the only name he recognized as his name until grade school, is a completely different given name AND family name from what is officially known.
Kind of a weird hypothetical situation, lets just go with it;
So if this man or woman in question "admits" that he is mr. xyz when asked, but on the inside has a name that is not actually on any records, but means the most to this individual, not to mention the name written in his or her family tree.
what then?
Is it just semantics at this point and I should just drop it?
Not trying to be difficult, just.. curious. Asking for a friend.