Aja, or Annada Ekadasi, is observed during the waning phase of moon (Krishna Paksha) in the month of Bhadrapad in
King Harischandra was famous for his truthfulness and honesty. Once Sage Vashista praised the truthfulness of Raja Harischandra but Sage Vishwamitra was not ready to accept it and he decides to test King Harischandra. Vishwamitra vows to prove that Harischandra also lies.
As a result of Vishwamitra’s tests, King Harischandra had to give up his kingdom and family and had to take refuge in Kashi. He becomes an undertaker in Kashi. But never lies. He always upheld truthfulness and proper code of conduct.
One day the great sage Guatama met King Harischandra and the king narrated his sad tale to him. Sage Gautama advised King Harischandra to observe Aja Ekadasi which has the power to remove all sins.
The King observed Aja Ekadasi and continued his firm faith in truthfulness.
Soon Sage Vishwamitra accepts his defeat and restores the kingdom, half of his power and all the glory to Harischandra. By the power of observing Aja Ekadasi, the King also got back his wife and his dead son became alive.
King Harischandra ruled the kingdom for several years and finally got Moksha and reached the Vaikunta all with the influence of observing Aja Ekadashi.