Han Nom is based off Hanzi,you really have no clue about Vietnamese history do you....
嶺南摭怪,粵甸幽靈集,大越史記,大越史記全書,越史略,欽定越史通鑑綱目 etc,these are all written in Hanzi:woot:
Then again your take medieval Vietnamese myths at face value,there's not much I can expect from you.
The funniest part of it all...