The study aims to figure out differences in interpretation regarding ``Saints accept Ho Tu(河圖) as a rule`` mentioned by Chu Hsi(朱熹) centering around responses and opinions expressed by Toegye Lee Hwang(退溪 李滉) and Seongho Lee lk(星湖 李瀷). Chu Hsi`s interpretation on ``Saints accept Ho Tu as a rule`` is based on Xian Tian Lun(先天論) by Shao Yung (邵雍), and saints represented by Fu Xi Shi(伏義氏) analogized Ba Gua(八卦) based on the concepts of numbers and bearings of Four Symbo1s(四象) and defined directions with regard to Ho Tu Shu(河圖數) of four directions represented by Four Symbols. Toegye proactively accommodated Chu Hsi`s view, and it was materialized through disclosure of interpretational characteristics of Chu Hsi. In comparison, Seongho adopted a different standard from Chu Hsi by dividing Ho Tu Shu into odd numbers and even numbers while rationally analogizing Ba Gua Fang Wei(八卦方位) from Ho Tu based on larger or smaller numbers and bearings designated in accordance with characteristics of yin and yang of numbers. Different responses from Toegye and Seongho with regard to Chu Hsi`s interpretation unveil Toegye`s consistent respect for Chu Hsi and Seongho`s critical acceptance of different views based on efforts to figure out new reasonable alternatives, and it stems from their differences in attitudes toward studying. According to Confucian Analects(『論語』), it can be summarized as ``Passing down old ideas without creating new ones(述而不作)`` and ``Gaining new insights through restudying old material.(溫故知新)`` Such differences led to advancement of Chu Hsi`s philosophy during the early days of the Joseon Dynasty while paving the way for interpretation of scriptures based on silhak(實學).