This essay proposes an excursion into the labyrinth of Cai Peihuo's (1889–1983) self-reflection recorded in a diary that he kept between 1929 and 1936. Cai is canonized as an anti-colonial figure and one of the key players in the home front Taiwanese mobilization movement during the 1920s and 1930s when the island was under Japanese rule. The analysis of his diaristic writing is significant in two respects. First, it sheds light on the divergent manners in which this first generation of Japanese-educated, bilingual middlemen envisioned their futures within particular temporal and spatial settings. Second, it examines ways of comprehending how the recorded experiences of Cai's encounter with social change reflect his inner dilemma in identifying with the colonial Weltanschauung. To this end, I focus on those passages in the diary that elucidate Cai's linguistic activism, language proposals and orthographic alternations that characterize the diary narrative.