it just a matter of parents making an effort to educate their kids of their roots. i am a 5th generation singapore "yen". i do know where my ancestors orginated from, canton, kaiping. i also know the village name but cannot post here as that will expose my surname.There a ancestral hall there, i will make a trip there to put down my name and my son name to the records.
How do you know where your ancestors came from through their surnames? There are one million 'Tans' in Singapore. The only way to know where your ancestors came from is if they pass down the information through the generations. Many Chinese back then were given away as babies for a one dollar note.