Sakya is one of the most ancient Indian tribes. It makes a controversy whether there are still alive the Sakyan or not. Indeed, many Buddhist tribes try to relate with the ancient Sakyan race. Among them the most three strong claiming tribes are namely, Daingnet (Tanchangya), Chakma and Chak or Sak. It is quite difficult to decide who are really known as Sakya according to Myanmar chronicles. Indeed, in the Danyawaddy Ayedaw Bung” p-14, it states that, when the Arakan king attacked to the Sakyan, they have two dominated areas which they were known by Eastern Sakya and Western Sakya. That means the Sakyan had two kingdoms in 14th century A.D. One in the east and the other in the west, whereas the Arakan was geographically in the middle of the two kingdoms. In the eastern side of Arakan was Micchagiri (Present Thayet in Myanmar), whereas the western side of Arakan was not other than the Chittagong Hill Tracts. According to the 18th century A.D. documents preserved both in Tanchangya and Chakma, the traditional ballad called “Ginguli” which might have composed in 19th century AD, indeed Tanchangya and Chakma belong to Sakyan race. The Chakma Circle (Sak Circle) was extended in the east the Lushai Hill, in the west the Nizam Road in Chittagong, in the North the Feni River and in the south probably around the Matamuri River. If there could be found a document, where the Chak people dominated a kingdom in the western side of Arakan around Chittagong Hill Tracts, then they can claim, they are the Sakyan to whom Myanmar chronicles concerned. According to my knowledge there is so such history in the present Chak people who are known as Sak in Myanmar nowadays. Therefore, it can be said, Myanmar chronicles refer to present Daingnet and Chakma, who dispersed by the name of Tanchangya and Chakma in India and Bangladesh as Sakya in the history of ancient Myanmar. Then, what is the support for the Chak (Sak) for claiming the ancient Sakyan race? Indeed, according to their present name known in Myanmar and as far it is recognised the Chak as the Sakyan race in Myanmar coheres. Then, second question should ask them; did they have any kingdom or dominated area in the western part of Arakan? Although I replied earlier, here would be better to make them clear for those who know on them as Chak. If the answer is negative, there is definitely something to be considered as it is recorded in the Dhanyawaddy Ayedaw Bung. How about between Chakma and Tanchangya for claiming the descendent of Sakyan? Either Chakma or Tanchangya they never wrote as Chakma or Tanchangya after their name by 19th century A D. Such historical record enlisted the assigned “chief as headman in each area (mou-za) for Chakma as Sri Tilok Chondra Dewan and for Tanchangya as Sri Hichadhon Amu”[Satish Chandra Ghosh Edited by Ronjit Sen, Chakma Jati (Kolkata: Arun Prokashona, July 2010), 388.] . It is believed for the first time it was never as Chakma Circle, instead it should have been spelt as “Sak Circle” even in somewhere else mentioned in the Arakan history. To disperse the power of Sak people, the British separated the Sakya dominated area into three district councils in late 19th century A.D such as Mong Circle, Chakma Circle, and Bamong Circle. Therefore, according to record one could assume that the Tanchangya and present Chakma belong to Sakyan race. Perhaps the word “Chakma” in the history of Burma was never appeared. It could be that they have invented this name themselves, which could be due to some reasons. In the case of Tanchangya, they got their name by modifying the word Toin-gangya derived from the Toin River in the south-east Bangladesh and Myanmar border. However, whatever we may say either Tanchangya or Chakma we both belong to Sakyan race.
Ref:http://www.utacf.org/apps/blog/entries/show/43157748-sakyan-race-according-to-myanmar-chronicles-
Tongchangya World 