The 5th of May is “Tango no Sekku” which is a ceremony to celebrate a infant heir growth. Actually, it decorates with miniature helmet and armor but originally, it started Samurai society to contribute their helmet and armor to shrine.
Those protectors were important for Samurai and pray to god to protect their kid from evil with those.
These Gogatsu Doll with helmet and armor will present from the kid’s Grandpa and Granma.