What is by consensus "the first modern Korean novel, "Yi Kwangsu’s Mujŏng (Hear tless, 1907) has been considered as an expression of enlightenment, embodying the author’s idea of "af fective education" (chŏngyuk). Yi Kwangsu suggested that Korean culture wrest itself from the premodern sphere of influence of Chinese civilization and embrace Western-originated modernity. He wrote Heartless as a tale of the protagonist transforming the structure of "affect" (chŏng) through engaging in a modern-style amorous relationship, and nourish affective grounds for modernized morality. Despite such a progressivist program, Heartless in fact crucially refers to Korean literary tradition, and the protagonist’s "affective education" is hindered by the haunting residues of Confucian virtues, which he is expected to fulfill in his long-standing relationship with the daughter of his mentor. The novel’s narrative is thus structured by the temporality of repeated revisiting of memories of the lost cultural past, rather than by a teleological progress. This paper reads Heartless as a story that "mourns for the world of the past," just as the narrator states in its ending, and argues that the temporality of "mourning" (chosang) informs a Korean literary modernity that Yi Kwangsu practiced in this novel – a modernity in which progress coincides with mourning for the loss of the cultural past whose very existence Yi denied due to its deep relationship with Chinese civilization, a super fluous aspect for a nationalized culture.