The vachana is a short prose poem in spoken Kannada, unrhymed, unmetered, ending in a signature line that names the poet's chosen form of Shiva. It was the literary instrument of the Virashaiva movement of the twelfth century, and the movement used it to say things that could not be said in Sanskrit verse: that the temple is unnecessary, that the priest is unnecessary, that caste is a fiction, and that the body itself is the shrine.
Akka Mahadevi's vachanas are the ones that go furthest into the interior. They are addressed to Chennamallikarjuna, the lord white as jasmine, and they move between erotic longing, contempt for householding, and a cold clarity about the uselessness of religious performance. One recurring figure is that of an illicit affair: she is married to a mortal husband and in love with another, and the other is God, and the poems treat the conventional life as the adultery rather than the reverse.
The movement she belonged to did not survive intact as a reform within Shaivism; it became a distinct community with its own scripture and its own social organisation, and the vachanas became its canon. What survives in ordinary Kannada literary memory, though, is not the doctrine but the voice, and hers is the one most often quoted, in translation as well as in Kannada.