入

According to the Shuowen Jiezi (설문해자), the character 入 is a pictograph that represents the shape of something enclosing from top to bottom, symbolizing the meaning “inside” or “to enter.”

Another interpretation, based on ancient script forms, sees 入 as imitating the entrance of a primitive dwelling or cave—essentially the opening of a shelter that people would enter.

In Japanese shinjitai (modern simplified forms) and Simplified Chinese, the radical form of 入 has often been modified to resemble 人 (person) or other shapes (for example, in characters like 內/ 内 (inside), 全 (whole or complete)).

In Taiwan, however, they generally retain the original 入 form, except in specific cases like 兪 (also written 俞).