This dissertation explores the history of ideas concerning music in twentieth-century Japan through a singing movement known as Utagoe (“Singing Voice”) in postwar Japan. In view of music in twentieth-century Japan as a discursive space, this dissertation examines the historical continuity of what may be termed “musical reformism,” or the conception of music as both a means and object of reform. By investigating music as a body of works, set of practices, and discursive space, the dissertation examines music in Japan since the Meiji Restoration as a historical phenomenon of heterogeneous interests, participants, and historical and current-day implications. Though the Utagoe movement came into being after the end of World War II, its worldview was greatly influenced by concepts concerning culture and music in early twentieth-century Japan. Shōka, or songs introduced in music textbooks since the 1880s, represented the first concerted effort to establish singing as a means of moralization. Min’yō (“folk song”) apologists and the shin-min’yō (“new folk song”) creation movement in the 1920s-1930s sought to uncover and reinvent the Japanese nation’s historical essence that was supposedly found in min’yō. Such an ambition to re-create Japan’s “national music” also found expression in wartime singing movements. As Utagoe’s predecessor, Central Chorus (est. 1948) came into being under the Japanese Communist Party’s renewed emphasis on culture since 1946. Though the party’s leadership remained vague on the question of political leadership on cultural matters vis-à-vis autonomy of cultural producers, the Central Chorus appealed to both camps by engaging in both “cultural operation” activities into the workplace and intensive musical education. The Japanese Communist Party’s elevation of cultural struggle in historical importance as political struggle allowed formative Utagoe to legitimate its endeavors in the larger political context of creating “national music” toward Japan’s political and cultural independence. The life and historical remembering of “laborer-composer” Araki Sakae (1924-1962) suggest the persistence of Utagoe’s worldview based on “struggle” (tatakai). Araki’s musical works in the last years of his life vividly reflect the contemporary JCP-line notion of tatakai, in which the local struggle was framed as a part of the larger national Japanese struggle against “American imperialism” and “monopoly capital.” Araki is still remembered by Utagoe’s veterans for his aspiration to effect a social change rather than his compositions themselves. Araki’s music continues to be appreciated in its historical context of the Japanese people’s historic “struggle.” Utagoe’s concept of “national music” (kokumin ongaku) held that learning national music from other nations would help create Japan’s national music. Russian-Soviet songs were by far the most popular, based on the belief that the Soviet music establishment inherited both the Russian folk essence and the Russian national school of music. However, Utagoe’s national music rhetoric came under a serious challenge as American folk song entered Japan as simultaneously a protest music and commercial music genre in the mid-1960s. Though “national music” was removed from Utagoe’s statute 1975, Utagoe’s official language remains largely nation-based, assuming universality and timelessness of the nation in music. Utagoe’s musical repertoire also gave rise to utagoe kissa (“singing voice coffeehouse”), drink-and-sing establishments by which the term utagoe is remembered today. Among the “first-generation” utagoe kissa in Shinjuku, Tokyo, Tomoshibi (“Lamplight”) is the only surviving first-generation utagoe kissa through a branch location. Having survived the 1960s-1970s when utagoe kissa was going out of business by dozens across Japan, Tomoshibi survived as an institution and business by the hands of the willing staff who engaged in similar repertoires of music and action as the Utagoe movement. Tomoshibi’s brand of utagoe, too, would be characterized by activism. Nihon no Utagoe continues in operation in the late 2010s, still celebrating its history of struggle for peace in postwar Japan. Meanwhile, 2000s-2010 saw the proliferation of utagoe kissa as local events across Japan for Japan’s post-retirement generations in the late 2010s. Beyond the confines of nostalgia, they reveal malleable nature of utagoe in application and vaguely collective character in aspiration. To the extent that the typical organizer of an utagoe kissa event invokes a sense of community and value of singing a given song in contemporary contexts, utagoe at large still possesses a tint of “musical reformism,” still being variably contested and applied by self-proclaimed practitioners of utagoe.