Eboshi Parent and Child

...This name probably comes from the fact that they were given adult names in place of their childhood names after coming of age. In the Kamakura period, in samurai society, eboshi parents and children were treated as having a relationship equivalent to that of a real father and son. According to the Azuma Kagami, in 1189 (Bun'ei 5), Miura Yoshitsura was in charge of the ceremony to present the third son of Hojo Tokimasa with his coming of age, and he named him Tokitsura.

*Some of the terminology that refers to "Eboshi Parent and Child" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…この呼称は元服後彼らによって幼名に替えて成人名を与えられたことによるものであろう。鎌倉時代，武家社会において烏帽子親子は実の父子に準ずべき関係として取り扱われた。《吾妻鏡》によれば1189年(文治5)北条時政三男元服の加冠役は三浦義連がつとめ，時連と命名した。…

※「烏帽子親子」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