The capital of Tonkin Delta is Hanoi, a five-letter word. Hanoi is the capital of Vietnam and one of the most populous cities in the country. It is located in the northern part of the country and is the cultural and political center of Vietnam. The city has a long history, dating back to the 11th century when it was founded by the Ly Dynasty. Hanoi is known for its many temples, pagodas, and other historical sites. It is also home to a vibrant nightlife and a bustling street food scene.