Surname
"Surname" is a book in which Lee regroups "virtue" of Nozai from the viewpoint of Confucian scholars. It is said to be called "Surname" because it is close to induction in "moral virtue" and composed only of pure contents without interfering with sexuality. At the time, he studied purely scholarly philosophy for the first time, which has been regarded as a heresy, and has heard that he has opened a new horizon to comment and understanding of philosophy.