The Japanese historical rite that formally initiated young men into adult samurai society was genpuku.
Genpuku was a Japanese coming-of-age ceremony in which a boy received adult clothing, a new hairstyle, and often an adult name. It was particularly important among the warrior and aristocratic classes. The ceremony demonstrated that the participant had entered a new social status and could assume adult responsibilities.
The timing was not identical for everyone. It could occur during childhood or adolescence, depending on period, rank, family circumstances, and political needs. A prominent patron or lord might take part, especially when the initiate belonged to a samurai family.
Genpuku is sometimes confused with the modern national holiday Seijin no Hi. Genpuku was a premodern rite whose practices changed across historical periods, whereas Seijin no Hi is a modern public celebration for young adults. The two belong to different social and political settings.