The origin of this belief and cultural tradition cannot be verified, but this custom is still maintained in some areas. In some places, people will hold a ceremony after the child is born, write the child's name on a piece of yellow paper, and then burn it to show that the child has a connection with the earth treasure king bodhisattva. In addition, there are some other ceremonies and practices, all of which are to show respect for the Earth-treasure king bodhisattva and to bless the children.
In short, this is a belief and cultural tradition, and it is also a wish and prayer for a better life.