Idashi Hajime - Idashi Hajime

Japanese: イダシハジメ - いだしはじめ

...On the seventh night of the celebration, the newborn baby is named, and a grand celebration is held with the midwife, the mother of the baby's birth, the matchmaker's wife, and close relatives, in order to acknowledge the newborn baby as a member of this world. The "first outing" on the seventh night or eleventh day is called Uide, Idashihajime, Dezome, etc., and is the first time the newborn baby sees the light of day. In some lands, people put a sedge hat or a mutsuki hat on the baby's head and make offerings to the household gods, such as the hearth god, well god, toilet god, and house god....

From [Seven Nights]

...This is the first stage in the end of the mourning period for the new mother, and it is generally believed that the mourning period for the father ends on this day. The seventh night is also called Uide, Desome, Idashihajime, etc., and there is a ritual for the newborn baby's first appearance in the world. The newborn baby is covered in a diaper and a straw hat, and offerings are made to the god of the hearth, the god of the well, the god of the toilet, and the god of the house.

*Some of the terminology explanations that mention "Idashi Hajime" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…七夜の祝には生児の名付けを行い，産婆，実家の母親，仲人の女親，近親等を招いて盛大な共食の祝を行って，生児をこの世のものとして承認する。　七夜または11日目の〈初外出〉をウイデ，イダシハジメ，デゾメなどといい，生児に初めて日の目を見せる。菅笠やむつきをかぶせて竈神，井戸神，厠神（かわやがみ），屋敷神などの家の神々に参って供物をする土地もある。…