Japanese kanji 亜

Read 亜 through its compound: it marks what comes next or ranks below.

The surrounding word sets the nuance: 亜流 can call a work derivative; 亜種 is a subspecies; 亜熱帯 means subtropical; and 亜硫酸 is sulfurous acid, the lower-oxygen counterpart of sulfuric acid. 亜細亜 is an older written name for Asia.

In the Shuowen Jiezi, an early Chinese character dictionary, 亞 is explained through a concrete shape and the sense “next in rank.” Later readings identify the shape as an ancient dwelling foundation or a tomb chamber, so its origin is not a settled picture. The form 亜 appears in variant-character records from the Song–Yuan period. In Japan, 亜細亜 and 東亜 appeared in Asian-solidarity writing and, during the late 19th to early 20th century, in rhetoric tied to Japanese imperial expansion. For neutral geography, 東アジア is clearer.

Are 亜, 亞 and 亚 interchangeable?

They are related forms, but each belongs to a different writing standard.

In present Japanese use, 亜 is the common-use form; 亞 remains in some names and organizations. In the mainland Chinese standard, 亚 is the simplified counterpart of 亞. Match the glyph to the language and spelling convention of the text.