AbstractThis article examines opinions concerning fūfubessei (a married couple retaining their birth surnames) posted on an online forum. Recently, the topic of fūfubessei has once again come under a spotlight, since the Japanese Supreme Court upheld the constitutionality of the Civil Code Article 750, which stipulates that a married couple must choose either the husband's or wife's surname upon marriage registration. Owing to the large number of women forfeiting their surnames, the fūfubessei issue has often been researched from feminist perspectives, which may have hindered the voices of others. This article analyzes, using text mining (quantitative analysis) and discourse analysis (qualitative analysis), a large number of opinions from people of various cultural backgrounds. The results of this study reveal a diversity of beliefs and attitudes towards Article 750, reflecting the complexity of the issue. In general, proponents of reform claim the law violates equality, rights and liberty. From opponents...