Ioriten "&12349" is one of yakumono (punctuation marks and other special symbols [term used in printing]) put at the beginning of a song in Japanese. It is called "a part alternation mark" in English, and represented as U+303D in Unicode and as 1-3-28 in JIS X 0213. It was originally used as a symbol in Utai-bon (chant book) of Noh and in renga (linked verse). It is also called a mark of song.
With regard to shape, some theory insists that a mark with two peaks, as shown in the figure, is called ioriten and a mark with one peak which looks like a hiragana character 'へ' (he) is called gatten.
In a sheet music of a Noh song (Utai-bon), ioriten is used at the beginning of a word when a part of each Noh player including Shite (a main actor of a Noh play), Waki (a supporting actor) and Jiutai (Noh chorus) starts. "へ"-shaped marks were used at least in sheet music made after the Meiji period, and they are still being used as of 2008.
It is not clear whether there were two separate marks 'ioriten' and 'gatten' or the same mark was referred to both as 'ioriten' and as 'gatten.'
In contemporary writings, when song lyrics are inserted in prose, ioriten is generally put at the beginning of the lyrics in order to distinguish them from the prose. With regard to computers, however, a musical note (disambiguation), which is included in JIS X 0208, the standard character encoding scheme, is often used as a mark of song in World Wide Web and e-mail because ioriten is not included in JIS X 0208.
It is said that an opening single quotation mark in Japanese ("'") was derived from ioriten in modern times.