What reguon area or country borders china on the east?

China's eastern border mainly consists of the East China Sea and borders several countries and regions:

1. North Korea: China shares a land border with North Korea to the northeast.

2. Russia: China shares a border with Russia in the far northeast, near the city of Suifenhe.

3. Mongolia: Mongolia borders China to the north and northeast.

4. South Korea: China does not directly border South Korea, but they are separated by the Yellow Sea.

5. Japan: Japan is located to the east of China, across the East China Sea.

6. Taiwan: Taiwan is located just off the southeast coast of China.