I am an Asian girl of Japanese, Vietnamese, and Chinese descent visiting relatives in the USA.  really very interesing...because most japanese or chinese parents would never approve of intermarrying. Many east asians still view race by country. ANyways very interesting mix you are and i find it very hard to believe. As you know, there are quite a few Chinese living in various Asian countries other than the country of China. In Vietnam, the largest non-Vietnamese group is the Chinese which can make for a not entirely uncommon mix there of a parent of both Chinese/Vietnamese mix.    You forget also, that in some of the various wars in Vietnam, Japanese military personnel from Japan came and helped fight in some of those wars, and inevitably some of those Japanese married, like in all wars in history, and that Vietnam was in war for a very long period of time, 25 to 30 years straight, and the likelihood is even more likely for a coupling that includes Vietnamese descent whereas it might not be as likely of a coupling of other non-East Asian countries: the Vietnamese fought the French for independence that progressed to the battle for the type of government in Vietnam post-independence, the civil war in Vietnam which we took part in (The Vietnam War); then the Vietnamese fought the Khmer Rouge of Cambodia that ended the Khmer Rouge reign; then they fought China to stop China's incursion/invasion into their country, all of which events took place over the period of 25 to 30 years of war straight in that country.