Where are the "two Beijings"?

"Mo Dao and the two capitals are not far apart" is a poem by Liu Yuxi, in which the two capitals refer to Chang 'an and Luoyang, indicating that both Chang 'an and Luoyang in the Tang Dynasty can be called capitals.

"Peony Appreciation" and "Peony Appreciation in Sianshan Villa" are companion pieces. Tiaoxi Fishing in Conghua in the Southern Song Dynasty combined the verses of two poems into Peony Appreciation Poetry, while Guangqun Fangpu in the Qing Dynasty directly combined the two poems into Peony Appreciation Poetry. "The Annam Book, Appreciating Peony, was written by Liu Yuxi in Luoyang, while Appreciating Peony was naturally written in Luoyang, describing the peony in Luoyang in the Tang Dynasty. So the capital in the poem refers to Luoyang.

After the founding of the People's Republic of China, several experts thought it meant Chang 'an. In contrast, scholars in Southern Song Dynasty and imperial academy in Qing Dynasty are more convincing.