THE LAST DISCARD IS PLAYABLE (ARTICLE 298)

When the last tile is drawn from the wall, the game does not immediately end. If the tile completes the player’s hand, they may declare mah jongg. If not, they discard as usual.

The final discard may be claimed only for mah jongg, not for an exposure. If no one claims it for mah jongg, the game ends in a Wall Game (i.e., a draw).

Mah Jongg Made Easy describes a Wall Game as occurring “when all of the tiles have been picked and discarded, and no player has declared mah jongg.”

The important distinction is that an empty wall does not end the game; the final discard still has one opportunity to produce a winner.

Source: Mah Jongg Made Easy (2024, page 13)