This is called “Meimeisho”.
Which is created when newborn baby become 7 days old.
 Relationship (Example says “Eldest son”)
 Baby’s name (Example says “William”)
 Date of birth (Example says “May 7th, 2022”)
History of the tradition for newborns in Japanese culture.
Is ceremony which to be held on the 7th day after birth.
In the Heian period, the medical system wasn’t sufficient, therefore it wasn’t uncommon for babies to die within a few days of their birth. So on the 7th day, people celebrate your baby to live healthy for 7 days and continue to grow.
According to the one theory, the name given on the 7th day is a remnant of the idea that babies born u to the 6th day were given by God(Ubugami) and became humans on the 7th day. It is said that the baby who was born for 6 days was not allowed to give a name because he/she was like a god, and he/she gave it only on the 7th day.
Nowadays, it is common to write the baby’s name in writing on the seven nights, display it on the Kamidana (a household Shinto altar), and show it to everyone.
If you are interested in creating this art piece
Please message me. If you have any questions please feel free to ask me anything.
I am looking forward to hearing from you.