Amir Aczel Foundation

What is the Khmer Zero?

On November 29, 1920, George Cœdès announced an incredible discovery–one that would change forever how we attribute the origins of our numerals. Thirty years earlier the French archaeologist, Adhémard Leclère, in 1891 had found two stone inscriptions in the ruined temple at Sambor on the Mekong River. Sambor is some 300 kilometers northeast of Phnom Penh and holds a collection of ancient temples dating from the seventh century CE–a period referred to as “pre-Angkor,” earlier than the famous cultural achievements we know so well from the temple complex at Anghor Wat in Siam Reap, Cambodia.

The biased view promulgated by the respected British scholar G. R. Kay, was that traders from Greece had brought mathematics to India from the West. He vehemently opposed the idea that the nine numerals–so vital to mathematics–had originated in the East. But Cœdès believed that they were an Indian invention. As the oldest known zero had been discovered in India, Kay’s theory of a concept brought from the West to India, was not possible to refute. But now Cœdès had his proof. When he translated the text on the stone labeled k127 (his numbering scheme prefaced artifacts with “k”), he was stunned to find that the text recorded a date, using a small dot to mark the numeral “0” (zero): 605 of the çaka era (685 CE). And this inscription did not come from a temple found on a likely trade route between East and West. It was located in what Cœdès called an “Indianized” civilization, an Angkor kingdom strongly influenced by the cultures and customs of India. He had the proof to refute Kay’s pro-West contention that the great mathematical discovery of numerals, and the place-holding zero, could not have originated in the East.

Why is the discovery of the zero so important to the history of mathematics?

In the introduction to Amir Aczel’s book Finding Zero tells the history of the invention of numbers and his own quest to find k127, thought to have been lost. He says:  “The invention of numbers is one of the greatest abstractions the human mind has ever achieved. Virtually everything in our live is digital, numeral, quantified. But the story of how and where we got these numbers we so depend on has been shrouded in mystery.”

Cambodia has had a long and complicated history. The country, with its rich history and culture, is just now emerging from the aftermath of suffering at the hands of Pol Pot and  the Khmer Rouge in the late 1960s through 1970s. The Khmer Rouge nearly 2 million Cambodians and destroyed or looted nearly 10,000 artifacts. Many believed that k127 had been lost or destroyed during this period. Because of Amir’s longstanding fascination with the origin of the numerals, his search for 127 was a personal one. Also, he felt strongly that the story of the history of the origins of the numerals should be told, and particularly, the world should be made aware of the important contribution of Khmer civilization to this history. This was particularly important to him as he knew that the Khmer Rouge had not only destroyed physical artifacts, but also had attacked Cambodia’s education system. Amir hoped to use the story of this ancient mathematical invention to encourage and promote interest in mathematics generally among new generations of Cambodian scholars and school children.

Read more the Khmer Zero

New York Times Review by Amir Alexander

Huffington Post by Amir Aczel
Scientific American Interview with Aczel