In the 1947 boxing tournament, he won the Bantamweight class and became Champion, and newspapers started to call him Kyar Kalay Ba Nyein.
Because of this, Kyar Ba Nyein was selected to compete on behalf of Burma in the 15th Olympics held in Helsinki, Finland, in 1952.
His numerous articles, stories on World Boxing matches, news reports, and sports news commentaries were later published regularly in magazines and journals such as Myawaddy, Thwe Thauk (Comrade), Mogyo (Thunder) and Tagun (Banner).
He trained hundreds of young boxers, and was appointed a boxing trainer in 1954 by the National Fitness Council.
Kyar Ba Nyein was so proud about the success of his boxers that he once told Ludu Daw Ah Mar that he never got serious injuries or scars during his 50 boxing matches, including seven with foreigners.
Kyar Ba Nyein was a pioneer who drew up the modern scientific rules and regulations that have been used since 1953 for Burmese traditional boxing, or Lethwei.
[12][13] He went around all of Burma, especially up to the Mon and Karen states, near Thailand, where there are a lot of villagers actively training in Lethwei.
He then trained them with the new methods and encouraged them to fight in the Burmese traditional boxing matches, which he had organized around the country[13] and even once, in October 1960, to Beijing and Shanghai, China[14] where he led about 100 boxers to show Lethwei, at the signing ceremony of the Burma-China border treaty.
He also organized goodwill matches by leading a group of Burmese traditional boxers to Thailand.