The Kujang sulhae [Japanese source]: Nam Pyǒng-Gil's reinterpretation of the mathematical methods of the Jiuzhang suanshu

In this article, a discussion and analysis is presented of the Kujang sulhae by Nam Pyǒng-Gil (1820-1869), a 19th-century Korean commentary on the Jiuzhang suanshu. Nam copied the problems and procedures from the ancient Chinese classic, but replaced Liu Hui's and Li Chunfeng's commentaries with his own. In his postface Nam expressed his dissatisfaction with the earlier commentaries, because the approaches of Liu and Li did not match those of his contemporary readers well. This can be seen from the most important features of Nam's commentary: the use of a synthesis of European and Chinese mathematical methods, easy explanations appealing to intuition, and disuse of the methods of infinitesimals and limits in Liu's and Li's commentaries. Based on his own postface and these features of his commentary, I believe that Nam Pyǒng-Gil treated the Jiuzhang suanshu as a very important historical document, which he intended to expla