[Yi Jian Fang Lun by Cheng Lvxin]

Yi Jian Fang Lun, also titled Cheng's Yi Jian Fang Lun, was compiled by Cheng Lvxin, a doctor in the Xin'an medical school in the late Ming and early Qing Dynasties. It was found that the book, as the version of Kang Xi, was published at Zi Mu Tang in the thirty-second year of the Deca You in the period of Kang Xi (1693). The version of Jia Qing was published in the twenty-second year of the Ding Chou in the period of Jia Qing (1817) by Shi Yunyu at Du Xue Lu in the Wu County. The Jia Qing version retained the "Preface of Mao Jike" from the Kang Xi version, deleted other prefaces, but added a "Preface of Shi Yunyu," and reversed the order of the bibliography with the "Cited Examples". The versions of Wen Hui Tang and Qiu Wo Zhai appeared in the year of twenty-four Jia Chen (1844) in the period of Dao Guang based on the version of Jia Qing. A copy of the transcript based on the Kang Xi version was found in Japan, containing volume III and IV. As a book of formulas, Yi Jian Fang Lun summarized the theory and application of formulas and the rationales of predecessors. It provides an effective practical paradigm for the following generations.