The Miao ethnic group's heroic epic King Yalu has been published in written form after being passed down orally for more than 2,500 years.

Spread among people from the extraordinarily isolated Mashan area of western Guizhou province, the epic hails the greatness of the Miao's forefather and chieftain King Yalu. It depicts the Miao's origin, migration and history.

"Its cultural value equals that of the other three ethnic epics - the Tibetan King Gesar, the Mongolian Jianggar and the Kirgiz Manas," Chinese Folk Literature and Art Society chairman Feng Jicai said at the monograph's release in the Great Hall of the People on Feb 21.

But unlike the other three, King Yalu is mostly sung at funerals. Its many rules and taboos define it as being functional rather than entertaining. The epic is passed down only by word of mouth among specially designated epic singers called "dong lang".

This group of cultural inheritors has shrunk to around 3,000 among the 300,000 people living in Mashan. Most of them are elderly, and the oldest is already 93.

The Chinese Folk Literature and Art Society listed the epic as a major project of the Chinese Folk Art Heritage Rescue Project in 2009, when it first captured the attention of art circles.

It was inscribed in the third batch of State-level Intangible Cultural Heritage listings in June 2011.

The new monograph contains about 11,000 lines of the epic, and photographs and field reports.

The Miao pronunciations of all of the lines are represented in the International Phonetic Alphabet, along with Chinese translations.

"This is only volume 1," says Yang Zhengjiang, collector, editor and translator of the epic.

"The entire King Yalu story is estimated to have more than 26,000 lines, which would require at least four volumes."

Chinese Academy of Social Sciences' Institute of Ethnic Literature director Chao Gejin agrees.

"King Yalu is a unique and compounded epic that mixes the Miao's origin, migration and heroic history, which require continuous study."

Folk literature scholar Liu Xicheng says: "It's astonishing that King Yalu's detailed family tree of more than 200 heirs has been passed down from generation to generation through songs that remain vivid today. The epic is the Miao's living encyclopedia."

Liu says that while more research is needed to ascertain an accurate time for the epic's creation, its first written form will open a new chapter in the history of the Miao and even of other ethnic groups.