The controversy regarding the late-compiled Ancient-Scrip Shangshu extended over several centuries. It was initially instigated by Song宋 and Yuan元 scholars, including Wu Yu吳棫 , Zhu Xi 朱熹, and Wu Cheng 吳澄, who introduced a skeptical approach toward the classic. Subsequently, during the Ming period, scholars such as Mei Zhuo梅鷟 and Hao Jing郝敬 conducted textual investigations that revealed significant doubts regarding the work. Amid this fervent debate, neighboring Korea and Japan—through diplomatic book acquisitions and cultural exchanges—gradually became attentive to the issues of authenticity associated with the late-compiled Ancient-Script Shangshu古文尙書, influenced by the scholarly debates of the Ming 明 and Qing 淸periods. A survey of Chinese texts in both countries, however, indicates that the debate resonated more profoundly in Korea than in Japan. This discrepancy can be attributed to the fact that Zhu Xi’s Neo-Confucianism served as the foundational norm for all ritual practices during the formation of the Korean state. Zhu Xi regarded the sixteen-character method for cultivating the mind—“人心惟危，道心惟微。惟精惟一，允執厥中”—as the self-cultivation technique practiced by the ancient sage-kings of the Three Dynasties. Notably, the chapter Dayu Mo, which records this method, is included in the late-compiled Ancient-Script Shangshu. Accordingly, this paper focuses on seventeenth-century Korea, investigating how Korean Confucian scholars of that era perceived the authenticity issues related to the late-compiled Ancient-Script Shangshu.