Abhidhamma Day

After Buddha spent three months teaching Abhidhamma or Ultimate Truth to his deceased mother, Santusita Deva and other Devas and Brahmas in Tavatimsa Devaloka, he returned to the human abode on the full moon day of Thadingyut, the seventh month of the Burmese lunar calendar. The full moon day of Thadingyut is marked at the noble day of Abhidhamma.