Since Japan's triple disaster of March 11, 2011, music has served to inform and give voice to unspoken opinions in several spaces—cyberspace, recordings, festivals and concerts, and public demonstrations. In particular, music has been an integral part of antinuclear demonstrations: here, music functions not only as an expression to be heard, but also—and perhaps more importantly—as a mechanism for encouraging participation and building solidarity among antinuclear citizens. Music has long been a part of demonstrations in Japan: percussive instruments and the rhythmic eejanaika (why not) call-and-response pattern were featured in demonstrations since the end of the Edo Period. Today, demonstrations in Japan include stationary demonstrations (kōgi), in which protesters voice claims in front of the offices of the offending parties, such as the prime minister, the Diet, or TEPCO. There are also “demos,” in which protesters walk through parts of the city; they are often preceded and/or followed by rallies, in which speeches by politicians and activists alternate with musical performances. In the weekly Friday kōgi in front of the prime minister's office (Kantei)—among the largest and longest-running weekly demonstrations Tokyo has ever seen, attracting 200,000 protesters on June 29, 2012, and running without a break for an unprecedented 19 months—drummers and horn players accompany the protesters’ calls and responses of slogans (Sprechchor), while folk singers, traditional drummers, chanters with uchiwadaiko, and fans of the late rocker Iwamano Kiyoshirō play in different spots around the block. In marching demos—which attracted 15,000-20,000 people per event in 2011, as many as 200,000 in 2012, and up to 60,000 in 2013—drum corps, brass bands, chindon bands, and other ambulatory musicians perform alongside “sound trucks,” piled with sound equipment, upon which rappers, singers, DJs, and bands perform. “Sound demos”—the name given to some demonstrations with sound trucks—have been credited with attracting masses of first-time demonstrators. In addition, protesters often credit the performances of musicians for establishing the mood of a demonstration. Drawing from the theories of Charles Tilly and Thomas Turino, this article focuses on the music of ambulatory demonstrations and explains the political catalysts for shifts between two styles: presentational and participatory, which I define below.