After visiting Hue, and seeing some of the Lunar New Year related preparations in the streets of Saigon, the thing that strikes me about Vietnam is that it is probably the most Chinese-influenced of any of China's neighbors that I have visited.
Looking around at the Imperial Tombs in Hue and whats left of the Citadel, the colors that jump out are yellow and red. Those imperial colors are kind of familiar aren't they? The whole terminology of rulership (Mandate of Heaven) and so many of the rituals that the Vietnamese Emperors performed as part of their duties (sacrifices every year at the Temple of Heaven in Hue), are the same as those conducted by the Chinese emperors.
The tour guide in Hue made no effort to hide the fact that so much of the imperial court's rituals and style was Chinese derived. He almost made a point of it to me specifically that China was the source.
The influence also seems to extend into the day to day life of people on the street. Whenever we passed by an open living room in Saigon we came across ancestor worship altars. When I flipped on the TV, I came across multiple TV channels showing Chinese language soap operas being dubbed into Vietnamese. During my final days there I read "Catfish and Mandala" by Andrew X. Pham. He talks extensively in his book of how his parents fixated on Face, relative social status, and differentiating themselves from others around them as a way of motivating their kids. Pham is not from Vietnam's Ethnic Chinese population, but his parent's value system is a carbon copy of their Chinese counterparts.
What's so special about all this? Because up until the French & the Americans came, China was the bane of Vietnam's existence. Vietnamese history is littered with battles and rebellions against various imperial Chinese dynasties. Yet Vietnam, more so than say Korea or Japan, adopted China's culture -- the rituals of the Imperial Court and the value of system of the man on the street.
Vietnam also, at least in my experience, isn't really thought of by either the East Asian studies scholars I studied with in college, or my older Chinese relatives who harped constantly about China being the root of all things Asian, as being part of the same family of East Asian cultures. It was never specified exactly what membership in this family entailed, but general outlines were the influence of classical Chinese culture -- usage of Chinese characters for written communications, Buddhism, Confucianism.
Seems to me the Vietnamese have no problem acknowledging the Chinese influence in their culture, but the Chinese have difficulty acknowledging the Vietnamese into their cultural sphere of influence.