With the development of social media

the dissemination of popular music has gradually shifted from one-way dissemination to interactive participation. In this process

fans are no longer merely recipients of content. They also participate in content dissemination through commenting

sharing

translating

discussing

and creating derivative works. Taking YOASOBI as a case study

this paper examines the relationship among official communication

fan participation

and the formation of fan communities on social media. The paper begins with a review of relevant research and then outlines its analytical approach in conjunction with the research design. Existing research indicates that social media enhances the sense of interaction between idols and fans

amplifies connections among fans

and further influences a sense of belonging and identity[1]. However

most existing studies focus on K-pop

Western pop culture

or general fan research

and discussions on the cross-cultural community formation process of specific J-pop groups remain insufficiently detailed. Based on this

this study posits that YOASOBI's social media practices

fan engagement behaviors

platform rules

and internal community norms collectively drive community formation. This study plans to conduct a comprehensive analysis of official content

fan interactions

and individual experiences through text analysis

online ethnography

and semi-structured interviews. This study aims to demonstrate that J-pop fan communities are not the result of spontaneous emergence

but rather dynamic structures gradually established through continuous interaction.