Yoshiko Yamaguchi was born in 12 February 1920 to Japanese parents, Ai Yamaguchi and Fumio Yamaguchi, who were then settlers in Fushun, Manchuria, Republic of China. Fumio Yamaguchi was an employee of the South Manchuria Railway. She was born in a coal mine's residential area in Dengta, Liaoyang.
From an early age, Yoshiko was exposed to Mandarin Chinese. Fumio Yamaguchi had some influential Chinese acquaintances, among whom were Li Jichun and Pan Yugui. By Chinese custom for those who became sworn brothers, they also became Yoshiko's "godfathers" and gave her two Chinese names, Li Xianglan (Li Hsiang-lan) and Pan Shuhua (潘淑華).