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Ask the Slot Expert: Does a Slot Machine Know How Many Coins I've Played?

12 December 2012

By John Robison, Slot Expert™


First off I want to thank you for all the interesting info you share with slot players like myself. I've learned so much.

In your Dec 5, 2012 article ("Does the Machine I'm Playing Affect My Chances for Hitting a Progressive Jackpot?") you stated the following:

"If the play results in winning the progressive jackpot, the machines sends a message to the progressive controller that the progressive has been hit. The progressive controller then broadcasts a message to all of the machines in the progressive letting them know that another machine has hit the progressive and resetting their progressive meters."

You have said the slot machines don't know how many coins have been played on the spin; that it's the RNG that determines whether you win or lose. What if you're playing a 3-coin progressive with only 2 coins per spin and hit the jackpot? Does the message still go to the progressive controller thus resetting their progressive meters? If it does and the meters reset, that would cheat full-coin players from their chance at the jackpot. If the message doesn't go to the progressive controller because it wasn't a full-coin spin, then would that not show that the slot/video game knows the amount of coins played and thus knows you haven't won the progressive?

If the machine knows you haven't played the max amount to win the progressive, then it makes sense that it knows how many coins you are playing and awarding your wins per your bet. There's so many scenarios that can be made if the machine knows your bet. So are the full-coin progressive players being cheated from a jackpot due to a lower coin bet or does the machine know your bet and award accordingly?

Thanks for your time and answer,

Dear Bonnie,

Thanks for the kind words.

I may have lapsed a few times, but I've tried to be careful to say that the RNG does not know how many coins have been played, not that the software running the slot machine does not know. In fact, some jurisdictions have regulations explicitly stating that the RNG cannot be affected by the number of coins played.

The software running the machine, of course, has to know how many coins you played. The software has to report it to the slot club system and to the casino's slot accounting system. The software also uses the number of coins played to determine whether the combination on the payline is a winning combination -- Did you play enough coins to activate the payline? If the machine is a Buy-A-Pay, did you play enough coins to active the combination? If you have a winning combination, the software then uses the number of coins played to determine who much to pay you.

The number of coins played affects many aspects of a machine, but the one thing it has no influence over whatsoever are the numbers generated by the RNG function.

Let's look at a short-coin play on a progressive. The player puts in one coin, hits the spin button and -- believe it or not -- three jackpot symbols land on the payline. The software determines that the combination is a winning combination. Then it looks at the number of coins played to determine how much the player won. It has an internal table that tells it that three jackpot symbols with one coin played pays, say, 1000 coins. If the player had played full-coin, it would send a message to the progressive controller to let the controller know that it hit the jackpot. Instead, it adds 1000 credits to the meter and gives the player an electronic raspberry for playing short-coin on a progressive machine. (Okay, it doesn't do that last part.)

The controller only cares when someone wins the progressive. It doesn't care about players hitting the combination but not winning the progressive because they played short coin. Those short-coin jackpot hits don't have any affect on when the progressive will be won. The only affect they have is on the amount of the progressive -- increasing it like any other spin on the machine.

It would be illegal for a progressive system to reset the progressive amount without having awarded the progressive to a player. The amount above the reset amount came from the players and belongs to the players. In many, if not all, jurisdictions, casinos can't just shut off a progressive. They either have to wait until someone hits the progressive or they have to move the portion of the progressive above the reset amount to another progressive system. It has to go to a player, not the casino.

Jackpots for all,

John Robison
John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

Books by John Robison:

The Slot Expert's Guide to Playing Slots