The Heavenly Hand and its Value (Article ID 41)
Abstract: If after the tiles are dealt out, and before the Charleston begins, East player has mah jongg it is referred to as a Heavenly Hand. When the game ends, the winner (East) is paid double the value of the hand.
Question from a player: What is the value of a heavenly hand?
Answer from the NMJL: “Exception: if East, who has 14 tiles, draws a Mah Jongg hand, the Charleston is waived. This is called a “Heavenly Hand”. East wins instantly and gets paid double from all.”
“If East has Mah Jongg before the Charleston begins, the Charleston is waived, and East declares Mah Jongg immediately. This is referred to as the “Heavenly Hand”. It is considered a self-picked Mah Jongg, and the winner collects double from each player.
Source: Mah Jongg Made Easy (2020 page 12 The Charleston; page 14, para. 6) https://www.nationalmahjonggleague.org