North Player Forgot to Take Their 13th Tile (Article ID 63)
Abstract: If, after the picking, north position player (the player to the left of East) realizes they did not pick their thirteenth tile, they can do so, but only before the Charleston or before East has discarded their first tile.
Question from a player: I am the fourth player sitting to the left of East and I forgot to take my 13th tile. Is my hand dead?
Answer from the NMJL: “Should any player’s hand contain the wrong number of tiles before the Charleston, the tiles are thrown in and the wall is broken again. If the player to the left of East has only twelve tiles after picking the tiles from the wall or after the Charleston, only this player may rightfully pick the thirteenth “tile if East has not discarded the first tile.”
Source: Mah Jongg Made Easy 2020 page 19 #9
Other answer from the NMJL:
“If the player to the left of East has only twelve tiles after picking of tiles from the wall or after the Charleston, only this player may rightfully pick the thirteenth tile before the Charleston or before East has discarded the first tile. ”
Source for other answer: National Mah Jongg League Bulletin Q&A (1987) https://www.nationalmahjonggleague.org