Sogana appears primarily in Heian era texts, most notably the Eiga monogatari and Makura no soshi. Originating from cursive forms of the man'yōgana characters, commonly occurring sogana were further adapted and by the early eleventh century had evolved into the forms of modern hiragana.
Sogana's principal, now only, function was artistic effect. It was often used for the rendition of poetry, as in the work of Fujiwara Kozei, whose style is often cited to exemplify the use of sogana. However, attribution of the few surviving sogana works is disputed.