P'ing-jang

Next, the Chinese text says that they set forth from the district of Lo-lang, which is situated not in Leao-tung, but in Corea, and of which the capital is the present city of Pʽing-jang (in d’Auville’s map, Ping-yang), situated upon the northern bank of the Ta-tʽung-kiang, or Pʽai-shue, a river of the province of Pʽing-ngan, which, in great part, in the time of the dynasty of Han, formed the district of Lo-lang.

Source: wiktionary

In A.D. 436 we find from the Kang Kien that Fêng Hung (馮弘) the last “Emperor” of Yen⁶² had to take refuge in the Tungusic (東胡) kingdom of Kao-li,—the very first mention of the new name,⁶³—which had been developing quietly at its capital P’ing-jang.[…] “The Emperor visited east-central China (江與京洛), and enlisted 400,000 soldiers and 500 Wu ships to cross the seas and go to P’ing-jang, (the Kao-li capital).”

Source: wiktionary

Accordingly an army was sent into Corea. It met the Japanese before the walls of Pʻing Jang (平壤), where it was annihilated and its commander, Tsu Chʻêng-hsun, (祖承訓), barely escaped with his life. The next Chinese army under the command of Li Ju-sung (李如松), fresh from a successful campaign against a Mongol rebel in Ning Hsia (甯夏), gained a victory over the Japanese in Pʻing Jang; but, elated by this success, the Chinese general allowed himself to be led into an ambuscade near Seoul and overthrown (1593).

Source: wiktionary

The Japanese defeated the Ming general Tsu Chʻeng-hsün 祖承訓 at Pʻing jang 平壤 in 1592, the first year of Bunroku 文祿 of Japan, and the fighting continued for some years; but at Hideyoshi's death the Japanese troops left Korea.

Source: wiktionary