Gamaka, also known as kaavya vaachana, is a form of storytelling by singing that originated in Karnataka, India.
One person reads a stanza of a poem with highest emphasis on meaning, applying suitable raga or a dhaati (melodic line), usually matching the emotion of the poem; the song generally has no established rhythm.
The emphasis in kaavya vaachana is on literature (Saahithya) and not on music where singer splits, compounds words in poems to make them easier to understand.
The poems are chosen mostly from old Kannada epics such as Karnataka Bharatha Kathamanjari, Jaimini Bharatha, Harischandra Kavya, Siddarameshwara charite, Ajita purana, Devi-Bhagavata, and Torave Ramayana and recently from that of Sri Ramayana Darshanam.
Harikatha is usually based on Telugu (and to a lesser extent other Dravidian languages) literature and the Vaisnava tradition, especially the tellings of the Bhagavata Purana.