Slot Machine Design Mathematics: What is a Progressive Jackpot

Connected jackpots, known in English as "Jackpot Link" or "Progressive Jackpot," translate to "Cumulative Jackpot" or "Cumulative Prize Pool." The term "Jackpot" implies a significant prize, and "Link" indicates that this prize pool connects multiple slot machines in a casino. When a player presses the Spin button, a certain proportion of the bet contributes to the jackpot pool, thus continuously increasing the amount in the pool. The more machines connected and the more players participating, the faster the amount increases.

In Macau, currently the most profitable gambling hub in Southeast Asia, jackpot prizes are usually several hundred thousand or even millions of Hong Kong dollars. In high-stake areas, you can even see amounts up to tens of millions of Hong Kong dollars! Casinos use this as an advertising and marketing strategy to attract gamblers to try their luck.

Next, PASA explains several types of connected jackpots through their payout mechanisms:

Mystery Trigger

Symbol Trigger

Mystery Symbol Trigger (a combination of the above two)

Mystery Trigger

A Mystery Jackpot means you do not know when you will win the jackpot, and the rules do not specify how the jackpot is awarded. The mechanism for triggering the jackpot is encapsulated within the machine, leaving players clueless.

Mystery jackpots usually define a starting and maximum amount. The jackpot is randomly triggered within this range and awarded to a specific player. However, this type of jackpot is slowly becoming less popular in casinos, though it can still be seen in some second-tier casinos in Macau or Southeast Asia.

Symbol Trigger

A Symbol Trigger means that the slot machine must display a specific pattern on the screen to win the jackpot. This is the most common type of jackpot seen in casinos or online platforms. Typically, the jackpot symbols are visible on the reels, and forming a line with them awards the jackpot.

This type of jackpot is represented by IGT's Megabucks.

Megabucks is widely seen in North American casinos, with a dedicated webpage recording each jackpot win, including the time and location of the win.

Mystery Symbol Trigger

What then is a jackpot designed as a combination of the two aforementioned types? Even if a specific symbol line is formed, it does not guarantee a jackpot. This type of jackpot is currently very popular in Southeast Asia, represented by "Duo Fu Duo Cai."

The rule states, "The appearance of the wild 'Fu' symbol on the screen may lead to a jackpot," meaning that to win the jackpot, the wild must appear on the screen. However, even then, an invisible probability control is still in play.