Question: What is a Heavenly Hand?

Answer: If the East player has Mah Jongg after the tiles are dealt out, and before the Charleston, it is referred to as a Heavenly Hand. At that point, the game ends, and the winner (East) is paid double the value of the hand.    

Source:  Mah Jongg Made Easy 2024, OTHER TIPS AND RULES FOR THE CHARLESTON, bullet #6