Five bodies - Ittsumi

...There are Fukuro Nagoya (hachisun Nagoya) obi that can be tied simply by sewing, and Kusun Nagoya and Fukuro Obi that are finished by inserting a core. In contrast to the Hon-Dachi (main obi) for adults, there are children's obi that are called Hitotsumi (one-year-old obi), Mitsumi (small obi) for 2-3 years old, Yotsumi (four-year-old obi), and Gotsumi (four-year-old obi) for 9-12 years old, according to the way they are cut. (2) Size There are certain standards for children, boys, and girls, and these are called standard sizes. ...

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

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…帯はかがるだけで締められる袋名古屋(八寸名古屋)，芯をいれて仕上げる九寸名古屋や袋帯がある。おとなの本裁（ほんだち）に対し，子ども物には1歳用一つ身，2～3歳用三つ身(小裁)，4～8歳用四つ身，9～12歳用の五つ身と裁ち方で呼ばれる用布がある。(2)寸法　子ども，男，女と一定の規準があり，これを標準寸法という。…

※「五つ身」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