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# How many stops on a slot reel?

2 April 2007

Hi, John,

In the old standard three-reel Double Diamond slot, how many symbols and blanks are there on each reel? There must of course be at least one Double Diamond symbol on each reel. Do you know how many of each symbol there is on each reel? I know there are many different machines, but I mean for the old standard 25-cent one that's been around for many years.

With the above info, I can at least learn the odds of hitting each pay line if it is truly random.

Sincerely,
John

Dear John,

Most slot machines have 22 stops on each reel, usually half symbols and half blanks.

Unfortunately, knowing how many times each symbol appears on the physical reel tells you nothing about the likelihood of hitting any particular winning combination.

Slot machines use virtual reels to determine the physical stop that will land on the payline. The virtual reels have from 32 to hundreds of virtual stops. Each physical stop appears one or more times on the virtual reel. The number of times the symbol appears on the virtual reel is what truly determines that symbol's probability of landing on the payline.

If you were to look at the reel strip on a typical Double Diamond machine, you'd find two Double Diamond symbols on it. You would think that there are 2 chances out of 22 that the Double Diamond symbol would land on the payline. If you could see the virtual reel, however, you would see that the true chances are something more like 2 out of 32, or 2 out of 64.

You can find more information about virtual reels by searching for "virtual reels" or Telnaes (the name of the man who patented the procedure) on this site and the Internet.

Best of luck in and out of the casinos,
John

On a recent trip to Hollywood Casino in Tunica, Mississippi, I was playing a quarter Jacks or Better video poker machine and held three cards to a royal, hit the draw button and the other two cards came up — Royal Flush. I continued playing the same machine and about three hours later I was dealt two cards to a royal, held them and hit the draw button and up came the other three cards — Royal Flush.

What are the odds of this happening on the same machine about three hours apart? I know one Royal Flush should show up about every 40,000 hands, but two on the same machine about three hours apart. A reply would be greatly appreciated.

James

Dear James,

I can't calculate a probability without knowing how many hands you played in between the royals. Both royals being on the same machine, in any case, is just a coincidence and the calculation would be the same even if you switched machines.

Suffice it to say that it is rare indeed to hit two royals on the same day, let alone within a few hours. You were very lucky.

Best of luck in and out of the casinos,
John

Send your slot and video poker questions to John Robison, Slot Expert, at slotexpert@comcast.net. Because of the volume of mail I receive, I regret that I can't reply to every question.

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
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