Seo-saeng BAK who came to Japan in 1429 made Kinshin (金慎), a student under him, investigate 'how to make a water wheel' closely and made him make a model water wheel, saying that 'Japanese farmers use water wheels,' and also reported a silver-gilding method, how to manufacture paper, how to generate vermillion and how to manufacture medicine called keifun.
1429年、日本に来た朴端生は、「日本の農人、水車の設けあり」として、学生の金慎に「造車の法」を精査させて模型を作り、鍍銀（銀メッキ）、造紙（紙漉）、朱紅、軽粉などの製造法を祖国に報告している。