Dr. Son is a former director of a fine arts museum in Hue, Vietnam’s imperial capital, and a specialist in Nguyen-era porcelain. He developed an interest in Vietnam’s territorial claims as a student poking around archives of old maps and documents.
In 2009, officials in Danang asked him to pursue his research on Vietnam’s maritime claims on the government’s behalf. He subsequently spent years traveling the world in search of material, including as a Fulbright scholar at Yale University.
Dr. Son has said the historical evidence of Vietnam’s maritime claims is so irrefutable that the government should mount a legal challenge to China’s activities in waters around some of the sea’s disputed islands, as the Philippines successfully did in a case that ended in 2016.
“I’m always against the Chinese,” he told The New York Times during an interview in 2017. But he said at the time that Vietnam’s top leaders were “slaves” to Beijing who preferred to keep the old maps and other documents hidden.
“They always say to me, ‘Mr. Son, please keep calm,’” he said. “‘Don’t talk badly about China.’”
The city of Danang, where Dr. Son lives and works, once had a reputation for its powerful, family-based networks that were willing to ignore dictates from the central government, said Bill Hayton, an author of books about Vietnam and the South China Sea and an associate fellow at Chatham House, a research institute based in London.
But Mr. Hayton noted that Vietnam’s current leadership, led by the Communist Party’s general secretary, Nguyen Phu Trong, has lately disciplined some key Danang political figures, including firing Nguyen Xuan Anh, the head of the city’s Communist Party Central Committee.
Even though Danang officials presumably supported and financed Dr. Son’s research, he added, “the current Vietnamese leadership does not want to rock the boat with Beijing and seems determined to keep a lid on criticism of China’s actions in the South China Sea.”