This study reconsiders inclusive music-making through the lens of new materialism. Drawing on Barad’s (2007) concepts of intra-action and diffractive reading and Bennett’s (2010) notion of thing-power—the vibrancy of matter—it explores how human and nonhuman agencies co-emerge in the pedagogical process of music creation. Rather than viewing learning as a human-centered activity, this study approaches it as a dynamic field where sound, body, space, and materials collaboratively shape the becoming of music.The inquiry builds on my previous post-qualitative study in which two five-year-old beginning pianists interacted with adult musicians during a jam session. The session emerged as a site of simultaneity and mutual resonance, where beat, rhythm, and musical communication unfolded through relational and material engagements. Three significant transformations were identified—participant, musical, and rhythmic—revealing that “beat” and “music” were not predetermined entities but emergent phenomena arising through heterogeneous intra-actions of human and nonhuman actants.Söderman (2025) further expands the discourse on inclusive music education by positioning hip-hop education as a holistic and emancipatory practice grounded in the Nordic tradition of Bildung, emphasizing self-cultivation and collective transformation. His discussion highlights how music education can be envisioned as a site of ethical and aesthetic becoming—a continuous interplay of body, material, and sound. Building upon this idea, the present study situates inclusive music-making within these dynamic entanglements of human and nonhuman forces.Drawing on qualitative case studies conducted in Japanese elementary and teacher education contexts, this study analyzes video recordings, field notes, and teacher interviews to explore two creative practices: (1) collaborative Japanese rap composition carried out across three elementary schools and (2) creative exploration using the traditional instrument koto. Each case is analyzed diffractively to trace how sonic, material, and affective forces intra-act to generate moments of inclusion, transformation, and shared becoming.This study demonstrates how teachers and students can co-create inclusive spaces of music-making by engaging with the material and affective forces of human and nonhuman agencies. By foregrounding the material vitality and distributed agency that give rise to musical processes, the study reconceptualizes music learning and teaching not as the transmission of predetermined knowledge, but as an assemblage (Deleuze & Guattari, 1980) of emergent relations in which teachers, students, and materials co-compose educational possibilities. Such a perspective provides philosophical and methodological grounding for inclusive, responsive, and transformative practices in global music education.