citizens of Myanmar annually celebrate Union Day on February 12. This holiday commemorates the Panglong Agreement signed in 1947.
The Panglong Agreement was signed by the Burmese government under Aung San and the Chin, Shan and Kachin peoples in Panglong, Southern Shan State. According to the agreement, Chin, Kachin and Shan peoples achieved full autonomy in internal administration.
Anyway, Myanmar didn’t achieve its independence in 1947. Aung San and six cabinet members were assassinated by political rivals in July 1947.