What countries in east Asia used to be a part of the Chinese empire but are now independent?

Several countries in East Asia that were once part of the Chinese empire but are now independent include Mongolia, which gained independence in the early 20th century, and Taiwan, which has operated as a separate entity since the end of the Chinese Civil War in 1949, although its status remains disputed by China. Additionally, Korea (divided into North and South Korea) was historically influenced by Chinese dynasties but is now fully independent. Vietnam was also part of the Chinese empire for over a millennium before achieving independence.