Thanks for Surviving, Not Just a Milestone

The specific ages the rite marks, three and five for boys and three and seven for girls by the most common convention, are generally traced to a set of separate coming of age customs practiced among the court and samurai classes of the Edo period, which were gradually combined into a single shrine visiting custom rather than beginning as one unified rite from the start. The underlying occasion for thanks was, for most of the custom's history, genuinely uncertain survival rather than a purely symbolic milestone: child mortality in premodern Japan was high enough that reaching each of these ages represented a real statistical accomplishment, and the shrine visit functioned as thanksgiving for having cleared a specific dangerous threshold rather than as a purely ceremonial rite of passage disconnected from actual risk.

As child mortality fell sharply over the twentieth century, the rite's practical urgency faded while its social and commercial elements grew, most visibly in chitose ame, thousand year candy, a long thin sweet given to children at the shrine and understood as a wish for long life, and in the now widespread practice of professional photography sessions in formal kimono or Western dress arranged around the shrine visit, a modern commercial layer added to a custom whose original occasion was considerably more anxious than festive.