it is generally assumed that the main theme of Sung-Ming Confucianism is nothing but the search for the way to attain “sage-hood.” This is a correct but oversimplified statement. Through displaying how Zhang Heng-qu’s interpretation of the “joy of Confucius and Master Yan” differs form Cheng Ming-dao’s, this paper intends to draw attention to a particular fact: the theme of every Confucian’s theory is different, and such a difference is important in terms of understanding their theories of self-cultivation. Zheng interprets Master Yan’s joy as happiness brought by the progress in attaining “sage-hood,” that is to say, the process of self-cultivation is tedious and laborious. Joy is just the occasional consequence of recognizing one’s progress in this process. On the other hand, Cheng always emphasizes the joy of a person who engages himself in self-cultivation, that is, the process of self-cultivation is a joyful experience. Every interpretation about the joy of Master Yan is reflected on the corresponding theory about self-cultivation. Zhang describes a person working on sage-hood as a diligent laborer; hence his theory about self-cultivation places particular emphasis on assiduousness. Believing that master Yan was joyous throughout his journey to sage-hood, Cheng would accordingly deny any assiduousness in this theory about self-cultivation; what he emphasizes is “no effort” and “no need to guard against evil.” Theories of self-cultivation are no doubt the answers to the question of how to become a sage. Zhang and Cheng are not answering the same question, even though both of them respectively provide a theory about self-cultivation. On the one hand, Zhang is only answering the simple question about how to become a sage, so his response to the question, successful or not, is a direct one. On the other hand, Chen’s question is how to attain sage-hood with joy rather than assiduousness. Thus even if Zhang’s response, due to it emphasis on assiduousness, can successfully answer the question about how to be sage, it is not the answer to Cheng’s question. Therefore, I conclude that it is an oversimplification to say that the main theme of Sung-Ming Confucianism is nothing but the search for the way to attain “sage-hood”.