The Evolution of Slots

The buzz and whirl of slots, or fruit machines as they are known in Great Britain, are inseparable parts of the ambience of the casino floor. Walk into any brick-and-mortar casino, and you are guaranteed to see at least several slot machines, with some of the larger gambling venues housing hundreds of them. The same goes for online casinos where you will find hundreds, even thousands of slot varieties.

In some parts of the world, the popularity of slots surpasses that of all other casino games combined. There are several reasons for this phenomenon. Slots are easy and very affordable to play, not to mention you can hit a life-changing payout with a small bet.

Modern online slots offer more engaging and entertaining gameplay due to their superior animations, special symbols, and bonus features. However, the first slot prototypes appeared long before the invention of computers and relied on mechanics to work. Let’s have a closer look at who invented this game and how it has evolved over the years.

The Prototypes of the First Slots

There are two accounts as to who developed the original prototype of the slot machine. One is that Charles Fey's Liberty Bell was the first device of this kind. The other is that New York-based company Sittman and Pitt manufactured a similar machine before Fey created his Liberty Bell.

A San Francisco Mechanic Creates the Liberty Bell
Herbert Mills and His Operator Bell
The Introduction of the Bar Symbol and Other Improvements

A San Francisco Mechanic Creates the Liberty Bell

San Francisco mechanic Charles Fey is often dubbed the Father of the Slot Machine although some believe he borrowed the idea from Sittman and Pitt, who manufactured a similar coin-operated gaming machine in 1891.

Sittman and Pitt’s creation resembled a video poker machine in that it used five rotating drums and fifty playing cards (ten cards on each drum). The gaming device could be played for as little as a nickel. The player would insert the money into a coin slit and pull a lever to rotate the drums along with the playing cards they contained.

The machines were installed in many saloons and bars, quickly drawing the attention of the public. It awarded payouts for five-card poker hands, with high-rank combinations paying more than low-rank hands.

The 10 of spades and the Jack of hearts were removed, which reduced the odds of getting high-ranking hands like the royal flush. Sittman and Pitt’s machine lacked a direct paying mechanism, so players were awarded soft drinks, free beer, and cigarettes.

The prizes varied depending on the establishment offering the game. At the time, it was impossible to devise a machine that could pay out automatically due to the high number of possible winning combinations in the card-based game.

It is believed Fey created his machine between 1887 and 1895 in his San Francisco workshop but the exact year remains unknown. Fey introduced several improvements to his slot prototype. He reduced the number of drums, or reels as they are called, from five to three, with each drum containing five symbols.

The symbols were diamonds, hearts, spades, a horseshoe, and a bell. Fey named his machine the Liberty Bell after the bell symbol. With fewer symbols and drums, it was significantly easier for the player to read a win. More importantly, Fey’s Liberty Bell was capable of paying prizes automatically.

The Liberty Bell machines are no longer in operation. Most were destroyed in the San Francisco earthquake of 1906, with only four machines surviving. A Liberty Bell machine from 1899 was exhibited as a gaming artifact in Reno’s Liberty Belle Saloon, owned by the inventor’s sons Frank and Marshall Fey, but the establishment was sold in 2006. The Nevada State Museum has been the home of the machine since then.


Herbert Mills and His Operator Bell

Fey’s invention inspired other manufacturers to design similar reel-based games. Among them was Herbert Mills of the Mills Novelty Company in Chicago. Mills’ company started manufacturing coin-based machines as early as 1896, including the Puritan Bell, the Mint Vendor Four Column, and the Operator Bell.

The Operator Bell was a knock-off of Fey’s Liberty Bell. This was a three-reel machine that weighed over a hundred pounds. Despite its significant size, the Operator Bell boasted two major improvements. Its coin slit was improved, but more importantly, it used new distinctive symbols. Instead of bells, horseshoes and card suits, the Operator Bell used fruit symbols like lemons, cherries, and plums.


The Introduction of the Bar Symbol and Other Improvements

Fey partnered with the Mills Novelty Company sometime around 1907. Slot machines were outlawed in San Francisco in 1909, which caused many manufacturers to move their operations to other cities, most notably Chicago.

Manufacturers like Mills tried to circumvent these restrictions by branding their machines as gumball dispensers. The card-suit symbols gave way to fruit symbols which represented different gum flavors.

Mills was the first to add an image of a chewing gum pack on the reels. It was then stylized as the bar symbol we all know today. The logo of the Bell-Fruit Gum Company served as the inspiration for the bar symbol.

Because of the ban, many slot machines at the time paid in products instead of cash. Some of the most common prizes were gum, cigars, and golf balls. The machines found their way into saloons, bars, bowling alleys, and tobacco shops. This is not to say slots with cash prizes did not exist at the time. They did, but the prizes were distributed covertly under the counter.

In 1916, the Mills Novelty Company manufactured the first “jackpot” coin-based machine. Improvements were made to the machines’ cabinets as well. Instead of using heavier and more expensive materials like iron, the manufacturers decided to use wood, which was cheaper and lighter. Some of the common themes for slot cabinets at the time included the War Eagle, the Lion Head, and the Roman Head.

Another major improvement took place in the 1930s when the Mills Novelty Company introduced the line of Silent Bell machines, which revolutionized the way slots played. The new machines awarded a double jackpot and were significantly quieter than older versions like the Operator Bell.

The popularity of slots was on the rise in the 1920s, with machines popping up across the United States. This continued until the Great Depression of the early 1930s when federal legislature outlawed gambling in all states but Nevada.

After the end of World War II, slots became a worldwide phenomenon, with an increasing number of governments embracing them to increase their tax revenue. The Mills Novelty Company expanded its operations to Europe, manufacturing more than 30,000 gaming machines during this period.

Bally and IGT's Contribution to Slot Development

Right until the middle of the 20th century, slot machines operated on a purely mechanical principle. The player inserted a coin and pulled a lever to make the reels spin. The machines contained springs, which caused the reels to gradually come to a halt. This created the illusion that players have control over the outcome, which further boosted the popularity of slots.

The 1950s saw the introduction of the first electromechanical slot machines. These were more advanced games with different paytables and multipliers where the prizes were proportionate to the number of coins players inserted into the machine.

Two of the manufacturers with the greatest contribution toward further slot improvement are Bally Technologies and International Game Technology (IGT).

Bally Takes Slot Machines to a New Level
IGT Enters the Slot Manufacturing Scene

Bally Takes Slot Machines to a New Level

Bally Technologies is yet another slot manufacturer to originate from the Windy City. The company was established in 1932 and initially went by the name Lion Manufacturing. It was later rebranded as Bally Manufacturing, borrowing its new name from one of its successful pinball games, called BallyHoo.

They later moved their headquarters to Sin City and changed their name to Bally Technologies, which presently operates as part of Scientific Games. After gambling was legalized in the state of Nevada, Bally was poised to dethrone the Mills Novelty Company from its position of slot manufacturing leader.

Bally went on to introduce several innovations, starting with the Bally Bell machine. This was the first slot in history that worked with two coin denominations. Players could feed the machine with nickels and quarters.

Electro-mechanical slots started to gain more traction in the 1950s. These games relied on a combination of electronic and mechanical components to operate. In 1963, Bally revolutionized the gaming industry by developing Money Honey, the first fully electronic game in the slot family.

Instead of pulling down a lever with strings, the player could set the reels in motion with a single press of a button. The nudge feature was also created at this time, enabling players to hold the reels to try and make matching symbol combinations on the next spin. As a result of these innovations, Bally manufactured as much as 80% of casino slot machines in the 1960s.


IGT Enters the Slot Manufacturing Scene

In the 1970s, William Redd, commonly known as Si Redd, created the first video poker machine intended for the mass market. Redd was working for Bally at the time. They turned down his idea because they were reluctant to branch out of their slot-manufacturing niche. This turned out to be a huge mistake on Bally’s part.

They allowed Redd to keep the patent for his video poker machine. Several months later, he left Bally and established his own company SIRCOMA (abbreviated from Si Redd’s Coin Machines). The new machines proved to be a huge success, which eventually led to the establishment of International Game Technology or IGT.

Hailing from Reno, Nevada, IGT dethroned Bally from its position of the world’s largest manufacturer of slot machines. The Reno-based company introduced many innovations that forever changed the way we perceive slot play.

One of its biggest accomplishments is the introduction of games with virtual reels that run on Random Number Generators. These games are known as video slots. You can read more about them in the next section.

The Advent of Video Slots

1Virtual instead of physical reels

The early 1980s were the beginning of a new era in slot-machine manufacturing. This is when the first video slots hit the floors of landbased casinos. Many players approached them with suspicion and were disturbed by the fact they used virtual instead of physical reels.

The games underwent some modifications to prevent cheating and were eventually approved by the Nevada Gaming Control Commission. Subsequently, they became a massive success among casino goers, giving them a greater variety of options.

2Accept banknotes

The new machines could accept banknotes so that players no longer had to carry around small change. This enabled them to play for longer periods, without interrupting their spinning sessions to exchange banknotes for coins.

3Wide-area progressive jackpots

The computerization of slot machines also worked to the advantage of gambling operators. It enabled them to experiment with different designs, themes, and payout variations. Wide-area progressive jackpots became reality with the introduction of the Megabucks slot by IGT in 1986. Machines at different landbased casinos were connected in a network. This allowed for the accumulation of multi-million cash prizes.

4Bonus games

Bonus games were added to further increase the entertainment value of slot machines. A company by the name of Anchor Gaming licensed its Wheel of Gold creation to IGT. The Reno-based company later obtained a license from the creators of the popular TV game show Wheel of Fortune and launched a slot with the same theme. The Wheel of Fortune slot remains one of the most popular games by IGT to this day.

5Multiple paylines

Slots with multiple paylines began to appear in the mid-1990s, with WMS being one of the leading developers to carve a niche for such slots.

Online and Mobile Slots

Online Slots

Mobile Slots

The rise of online gambling in the mid-1990s allowed slots to transition from the landbased casino floors to the screens of spinners’ desktop computers. The games whose availability was previously restricted to casino floors, bars, and saloons are now readily available to anyone with a computer and a reliable internet connection.

Microgaming is among the pioneers in gambling software development. It presently boasts the largest selection of online slots. The early slot releases were less advanced from a graphics perspective but have greatly evolved over the last two decades.

Today’s online slots boast highly realistic 3D graphics and animations, exciting bonus features, and a range of special symbols that increase their winning potential. The creations of software studios like Yggdrasil, Betsoft, Pragmatic Play, Playtech, and NetEnt are particularly impressive in terms of graphic presentation and gameplay.

The beauty of playing slots online stems from the enormous choice players are facing. There are classic slots, slots with multiple paylines, slots that pay for matching symbols on neighboring reels, and progressives capable of dropping seven-figure prizes.

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Summary of Key Improvements in Slot Machines

Slots have gone a long way since Charles Fey first devised his famed Liberty Bell machine. New advances in technology will surely bring more innovations to slot players. We can only wait and see what the future holds for reel spinners. For the time being, here is a summary of some of the most important improvements slot machines have seen over the last century.

Coin hopper
Progressive jackpots
Multiple paylines
Bill validators
Virtual reels
Ticket printers

Coin hopper

The coin hopper was introduced by Bally Technologies and ultimately changed the way slots played. It was first used in Bally’s Money Honey from 1963, enabling the game to circulate coins from bigger pools, which significantly increased the size of the payouts. Earlier games, on the other hand, used coin tubes which contained fewer coins because of the limited space in the machines.


Progressive jackpots

In progressive slots, a percentage of each bet goes to the jackpot amount, which continues to increase until a player wins it. The jackpot is then reset to its seed amount and starts building all over again.

The first progressive jackpots accumulated on isolated machines. Wide-area progressive games were introduced later, with slots in different casinos being connected to the same pool. This allows the jackpots to drop multi-million prizes. The first wide-area progressive game was IGT’s Megabucks, launched in 1986.


Multiple paylines

Multiple paylines are to be found in most modern video slots. Winning symbols must appear on one or more paylines for the slot to award a prize. In some games, the matches must occur in a specific direction, typically from left to right, although there are games that pay in both directions.


Bill validators

Bill validators have significantly improved the gameplay for landbased reel spinners. Back in the days when slots accepted only coins, players had to drop the coins one by one. The bill validator makes it possible for you to insert a banknote in the machine and receive the corresponding amount in credits. Modern bill validators are capable of scanning banknotes and payout tickets with bar codes. This not only increases flexibility for the player but makes it possible for casinos to detect forged banknotes.


Virtual reels

Virtual reels have made it possible for slots to drop enormous payouts. Before their introduction, the only way to increase the number of stops per reel was to increase its size. Manufacturers were restricted by physical space because the reels had to fit into the machines somehow. Virtual reels changed this, allowing game developers to produce slots with different volatility and larger jackpots.


Ticket printers

Ticket printers appeared in the 1990s to replace coin hoppers, enabling manufacturers to create games with smaller coin denominations and multiple paylines. The player simply presses a button when they want to collect their profits. The machine would then print a bar-coded ticket. The player can use the ticket for play on another machine or take it to the cashier cage and exchange it for cash.

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