On May 16, 1949, the PRC’s Renmin ribao 人民日报 (People’s Daily) carried a story about the change of name from Siam to Thailand. In 1939, Prime Minister Phibunsongkhram changed the name Siam to Thailand. At the end of World War II, the name was changed back to Siam, but then in 1949 Phibulsongkhram, who was again in power at the time, changed the name to Thailand again.
This is what the Renmin ribao report had to say about that:
“Siam’s fascist leader, Luan Piwen [i.e., Luang Phibunsongkhram] announced on the 11th that the name Siam had again been changed to Thailand. Note that the name Thailand is the extremely invasive and megalomaniacal name [created by] the Siamese fascists.
According to the fascists, the area of Siam’s jurisdiction includes China’s Hainan island, Yunnan, ethnic minorities within the area of Sichuan, and that everyone in these places are of the ‘Thai’ race.
Luan Piwen changed the name for the first time in 1939 on the eve of the Great War. At that time, Luan Piwen was carrying out his fascist terroristic rule and was fanatically discriminating against overseas Chinese, referring to them as ‘the Jews of Asia.’
In 1945, after the Japanese bandits surrendered, the Siamese rulers again put aside the name Thailand. But since Luan Piwen again took power, he is now using the name Thailand.
This demonstrates that under the encouragement of the invasive policies of the American and British imperialists, the Siamese fascists are returning to their old dream of ‘Great Thai Race-ism.’”
-Prior to the twentieth century people in Siam had not thought all that much about “origins.” It is only when Westerners came along and started looking for “races” and “origins,” concepts that were popular at the time in “the West” and important elements of nationalism, that some people in Siam started to think in the same way.
Works like William Dodd’s The Tai Race: Elder Brother of the Chinese (published in 1923) argued that the Thai people had originally come from China. In the late 1930s and during World War II, Phibunsongkhram used this idea to promote an extreme form of Thai nationalism, and that made some people in China angry, as the above account in the Renmin ribao indicates.
While today Chinese no longer write with the same degree of emotion about this issue, it is still an emotional issue for them. Liang Yongjia has a nice essay that covers the historiographical debates about this topic and the ways that Chinese historians have come to a forced conclusion about the place of the Tai/Thai in the Chinese past.