Hentaigana (変体仮名) is the term for alternative kana letterforms equivalent to standard kana characters. This is the legacy of manyogana, where many different kanji could be used to represent the same syllable; as these became simplified into cursive forms, hentaigana were the result. Hentaigana were used more or less interchangeably with their equivalent hiragana on an ad hoc, individual basis until 1900, when the hiragana syllabary was standardized to one character per mora.

The hiragana "syllabic n" (ん) originally derives from a hentaigana for /mu/, derived from the character 无. The spelling reform of 1900 separated the two uses, declaring that む could only be used for /mu/ and ん could only be used for syllable-final /n/. Previously, in the absence of a character for the syllable-final /n/, the sound was spelled (but not pronounced) identically to /mu/, and readers had to rely on context to determine what was intended. This ambiguity has led to some modern expressions based on what are, in effect, spelling pronunciations. For example, iwan to suru "trying to say," is ultimately a misreading of mu as n. (The modern Japanese form 言おう ioo comes from earlier 言はむ ipamu. Many other changes are seen here as well.)

Hentaigana are considered obsolete in modern writing, but a few uses still remain. For example, many soba shops use hentaigana to spell kisoba on their signs. Hentaigana are used in some formal handwritten documents, particularly in certificates issued by classical Japanese cultural groups (e.g., martial art schools, etiquette schools, religious study groups, etc). Also, hentaigana are occasionally used in reproductions of classic Japanese texts. Much like blackletter is used in English and other Germanic languages to give an archaic flair to text, hentaigana may be used to serve the same purpose in Japanese. However, most Japanese people are unable to read hentaigana, only recognizing a few from their common use in shop signs, or figuring them out from context.

External links

• Chart of hentaigana calligraphy from O'Neill's "A Reader of Handwritten Japanese" (in PDF)
• Yet another chart of hentaigana
• Chart of kana from Engelbert Kaempfer circa 1693
• Hentaigana on signs
• Mojikyo fonts including hentaigana and word processor support