In feudal Japan, boys of noble or Samurai families came of age at about fifteen years. A ceremony called Genpuku was performed at which the boy's forehead was shaved and his hair dressed in the adult style. He was presented with his first eboshi [court cap] and given his adult name. At the same time he would be presented with the swords that marked his rank, and in many cases an armour. This example is almost certainly one made for this purpose.
At approximately two thirds the size of a conventional suit, this armour is made as a functional defence.