Vietnam is a country in Southeast Asia, bordered on the North by China, on the West by Laos and Cambodia and on the East and South by the South China Sea, which is called "the East Sea" by Vietnamese.
Hà Nội is Vietnam's capital city, and is located on the northern part of the country.
Look at the map and zoom in Southeast Asia, you will see Vietnam which looks like letter S lying on the western coast of South China Sea.