Most people aren’t proud of that and they don’t even admit that Vietnam belongs to the Sinosphere. In their mind, Vietnamese culture is something so pure and wonderful, and it has been inherited from the Vietnam ancestors, and it was never affected by any other culture. Some “historians” got “famous” by “proving” Yi Ching and Chinese characters are invented by the Vietnamese. They hate China so much that they furiously decline any reliance between Chinese culture and Vietnamese culture.

And at the same time they don't really understand Vietnamese culture, many people believe ao dai is thousands of years old (It was invented in 19th century). They consider Chinese characters evil because it's Chinese, while Vietnam considered Hanzi the symbol of wisdom for many centuries.

Well that's sad, the heavy influence of Chinese culture in all aspects of Vietnamese culture is undeniable and it's an essential part of Vietnamese culture. Nationalism can get very wrong.

Edit: I totally don't know why such a negative answer like this can get this many upvotes, but thanks