The answer is China.
North Vietnam (capital was Hanoi).
China
North Vietnam hasn't existed since 1975 or there abouts. It's Vietnam since about 1975 (they won the war and united the country into one nation). Hanoi is probably still the capital; as it was during the war.
The capital city that is 1450 miles northeast of Hanoi Vietnam and 500 miles west of Pyongyang North Korea is Ulaanbaatar, the capital of Mongolia.
Hanoi is in the North of vietnam
Beijing, the capital of the People's Republic of China, is located 1450 miles northeast of Hanoi, Vietnam and 500 miles west of Pyongyang, North Korea.
North Vietnam.
Beijing
Hanoi in North Vietnam
Hanoi .
Beijing