Aichichi - Aichichi

...The first breast milk is called arachichi (new milk) and is not given as it is not good for the baby. Also, because breast milk production is poor, the custom of using someone else's milk for about two days after birth was widely practiced until around 1935. If the newborn baby is a boy, it is often asked to use someone who has a girl, and if the newborn baby is a girl, it is often asked to use someone who has a boy. This is called chiawase (milk combination) or aichichi. It is said that chiawase will ensure that the baby will grow up strong and that marriage will occur quickly.

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

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…最初の母乳はアラチチ(新乳)といって，よくないとして与えず，また母乳の出も悪いので，生後2日間くらいは他人の乳を用いる風習が昭和10年ころまでひろく行われていた。生児が男なら女児をもつ人，女なら男児をもつ人にたのむ場合が多く，チアワセ(乳合せ)，アイチチなどとよんでいる。チアワセをするとじょうぶに育つ，縁組が早いなどという。…

※「アイチチ」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報