Determining the Southeast Asian country most similar to the East Asia requires considering various social, cultural, economic, and political factors.
One way to answer this complex question is by analyzing the data from the Country Similarity Index. The index attempts to quantify how similar countries are to each other relative to other countries, using a variety of statistics from five broad categories: demographics, culture, politics, infrastructure, and geography.
(Southeast Asian countries are defined as Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam, East Asian countries are defined as China, Japan, North Korea, South Korea, and Taiwan)
While there are certainly other countries in Southeast Asia that are slightly more similar to East Asia in terms of demographics, infrastructure, and politics, Vietnam stands out as having by far the most similar culture to East Asia in the region.
One reason Vietnam’s culture is more similar to East Asia than the rest of Southeast Asia is religion. It is the only country in Southeast Asia that primarily follows Mahayana Buddhism. Vietnam’s historical ties with China led to the influence of Chinese Buddhism on Vietnamese Buddhism. This influence is evident in the architecture of temples and pagodas, the use of Chinese Buddhist texts, and the incorporation of Confucian and Taoist elements.
In addition, Vietnam is the least religious country in Southeast Asia. Like China, Taiwan, Japan, and Korea, the country has many atheists. Vietnam has a history of communist rule, and the government has traditionally promoted secularism and atheism as part of its ideology.
Before Vietnam switched to the Latin alphabet, it used Chinese characters. Many historical documents, texts, and inscriptions in Vietnam were written in Classical Chinese. Chinese characters are still used in various aspects of traditional Vietnamese culture, including calligraphy, poetry, literature, and religious texts.
The Most Similar East Asian Country to Vietnam
The Country Similarity Index suggests that China is the most similar East Asian country to Vietnam. It had been ruled by China several times in history, most recently in 15th Century. So its culture is more similar to China than other Southeast Asian countries. They both have high rates of atheism but also practice Mahayana Buddhism. One reason for the high rate of atheism is that the governments of both countries have been controlled by the Communist Party.