The story
From Japanese 平壤(へいじょう) (Heijō), the spelling 平壤 or its shinjitai form 平壌 are still used but now normally pronounced as ピョンヤン (Pyon'yan) in Japanese.
Etymology from Wiktionary, CC BY-SA 4.0.
Heijō
Today it means: Synonym of Pyongyang: the Japanese-derived name (during the Japanese occupation period in the early 20th century, now capital of North Korea). Full definition →