Question: Do I leave my tiles up on the flat part of my rack after my hand is declared dead?

Answer: If you exposed tiles and your hand is declared dead on a concealed hand, all the tiles are returned to the player’s rack (slant part).

If your hand was called dead on an exposed hand then the exposure (s) that made the hand dead, are returned to the player’s rack.

Both of these actions are done to prevent confusion regarding which Jokers are still available for an exchange.

Source: Mah Jongg Made Easy 2024, page 22, #4(b)