@Daniel Cheng
Dongjing, Nanjing, xijing, Beijing are all romanizations for the capital cities of the 4 cardinal directions (North, South, East, West)

Dongjing exists as Tokyo, the capital of Japan. Both kanji in Japan and Chinese characters write it as 東京.Tokyo’s old name was Edo, meaning mouth of a river.

In China:
Datong was named “Datong xijing governate” and once one of the five capitals of the Liao Dynasty and the temporary capital of the three dynasties of Liao, Jin and Yuan.
Fengxiang also known as the “Fengxiang governate” of xijing established in the Tang Dynasty
The former name of Chengdu, called xijing by a short-lived successor state to the Ming under the warlord Zhang xianzhong
The former name of xi’an under the Republic of China.
In Korea:
Old name of Pyongyang during the Goryeo dynasty, as its temporary capital city.
Cheongju, was one of the five small capitals of Unified Silla on the Korean peninsula.
In Vietnam:
xijing was a Chinese name for Thanh Hóa, the western capital of Lê dynasty in the 15th century.

东京、南京、西京、北京都是四个方位(北、南、东、西)的首都的汉字拼音。
东京存在于日本,是日本的首都。日本的汉字和中国的汉字都写作“东京”。东京的旧名是江户,意思是河口。
在中国:
大同被命名为“大同西京府”,曾经是辽朝五个首都之一,以及辽、金和元三个朝代的临时首都。
凤翔,也被称为唐朝建立的“西京凤翔府”。
成都的前名,在明末军阀张献忠的一个短命国家中被称为西京。
中华人民共和国时期西安的旧名也叫西京。
在韩国:
在高丽王朝期间,平壤的旧名叫西京,作为其临时首都。
清州是朝鲜半岛上统一新罗的五个小首都之一。
在越南:
西京是15世纪黎朝西部首都清化的中文名称。