Question: How do you play with a 5th player (Bettor)?

Answer: In a variation created by the National Mah Jongg League, a 5-player game is supported, often referred to as “playing with a bettor” or “5th player betting.” Here’s how it works:

The game begins with four players seated at the table, while the 5th player sits out and takes on the role of the “bettor.”

After the Charleston, the bettor selects the player they believe will win. They indicate their choice by using a betting disk, a betting cube (wheel), or by writing it down on a piece of paper. Each seated player is assigned a number, starting with player 1 as East and proceeding clockwise.

Once the bettor has made their selection, they place the betting disk, cube (wheel), or paper upside down on the table. From this point on, the bettor remains silent until the game concludes.

Payouts are made after the game ends. If the bettor chose the winning player, both the bettor and the winner receive the full value of the winning hand. However, if the bettor did not choose the winning player, the bettor pays the winner the same value as all other players. Except, if the player bet on throws the winning tile, the bettor and that player pays double. In the case of no winner, bettor is paid only if they bet on a wall game.

At the start of the next game, East relinquishes their seat, becoming the next bettor. The previous bettor takes the vacant seat.

By following these rules, the 5-player game with a bettor adds an exciting betting element to the gameplay experience.

Source: Mah Jongg Made Easy 2020, page 27, Five-Handed Mah Jongg