However, this radical is mainly used to categorize miscellaneous characters otherwise not belonging to any radical, mainly featuring a hook or fold, and 乙 is the character with the fewest strokes.

In the ancient Chinese cyclic character numeral system, 乙 represents the second Celestial stem (天干 tiāngān).

In mainland China, 乙 along with other 14 associated indexing components, including 乚, etc., are affiliated to a new radical 乛 (乛部), which is the 5th principal indexing component in the Table of Indexing Chinese Character Components predominantly adopted by Simplified Chinese dictionaries.

[1] Usually, only several out of the 15 variant components are listed under radical 乛 in dictionary indexes.

In the Unihan Database, 亀 (Japanese simplified form of 龜) falls under Radical 5 + 10 strokes, while other variants of 龜 (including Simplified Chinese 龟) fall under Radical 213 (龜 "turtle"), causing an inconsistency.