Who is the youngest 10 dan black belt and which country?

A 'real' black belt is usually not awarded to someone until they reach their teens. Many styles won't give a fully certified blackbelt until someone is high school age. 'Youngest age' means nothing if it isn't legitimate. I'm sure you can find 4 and 5 year olds that have been awarded a blackbelt, but the reality is that they do not have the maturity to have one