The History of Slots: The Story of How the Casino Slot Machines Started

Casino slot machines are fun to play and winning them is a dream for many people. They are also highly addictive. The game is quick, so winning can either be easy, or it can be very difficult depending on your skill and knowledge of the game.

Early History

Before the early 1980s, hitting jackpots, and the likelihood of doing so in slot machines per spin is tied to how many symbols and blanks, or “stops”, are there on each reel. The old electro-mechanical slot machines all had 22 stops per reel. That means, if, at that time, you logged all the symbols that land on each reel, it was humanly possible to calculate the odds of a jackpot on a given spin.


The earliest record of slot machines dates back to the late 19th century. The first mechanism to be identified as such is believed to be the creation of Sittman and Pitt in 1891. It was a game with 5 drums and a total of 50 playing cards. Players, usually from bars, would insert nickels and pull the lever to play. These slots were later tweaked such that the ten of spades and the jack of hearts don’t appear, significantly reducing the odds of getting a royal flush. The machine had no direct payout mechanism, so wins were paid at the bar with non-monetary prizes, like free drinks and cigars.

1887 – 1895


Sometime between 1887 and 1895, Charles Augustus Fey developed the first slot machines with automatic payouts, the Liberty Bell. The machine featured simpler mechanisms, trading the five drums with three reels. The cards in the game were also replaced by only five symbols –  hearts, diamonds, spades, horseshoes and a liberty bell, which gave it its name. Because Fey did not apply for a patent for his creation, it was later copied by other developers within the next few years. 

1902 – 1908


Despite the official ban on slot machines in 1902, the Liberty Bell lived on. However, because cash prizes can no longer be disbursed, the era of the fruit machine started. The new machines evolved into using fruit symbols, and the prizes became chewing gum and sweets. In 1907, Chicago-based manufacturer Herbert Mills created the Operator Bell. By 1908, the Operator Bell introduced its trademark BAR symbol and became a mainstay in many tobacconists, bowling alleys, shops and salons. 

The Next Developments

For many years, casino slot machines remained mechanical, employing levers that set the reels in motion. The game requires the players to pull down a lever, stretching a spring inside the machine which gradually stops the reels from spinning. The manual approach gave the slot players the feeling that they could control the game and the outcome, sending the slot machine to the top of mind as one of the most popular games. It is also because of this lever that the slang expression “one armed bandits” came to life.


In 1964, the first fully electromechanical slot called Money Honey was released by Bally. Unlike its predecessors, the Money Honey slots were operated electrically, and equipped with a bottomless hopper that allows automatic payout of up to 500 coins. However, the game still requires pulling a level to start as it would have been too unfamiliar to play the game without a lever. Later on, the familiar lever was also removed from new slots.

1976 – 1978

In 1976, the slots evolved and the first true video slot was developed. The new slot was created by the Las Vegas-based company Fortune Coin in Kearny Mesa, California. Unlike the earlier versions, this game used a modified 19-inch Sony TV for the display. After cheat-proofing and modifications, the video slot was approved for use by  the Nevada State Gaming Commission. It was then made available to the Las Vegas Hilton Hotel, later on becoming a huge hit  in the Las Vegas Strip. In 1978, Fortune Coin was acquired by IGT.



The first random number generators (RNGs) came into existence sometime in the 1940s. The RAND Corporation created them, but they were not used in any commercial software or hardware. The development of RNGs became a sign that computers will be useful in the world of gambling.

1980s and 1990s

In the 1980s and 1990s, the computing revolution began. At this time, many slot machine developers started using random number generators. Though the newer slots were improved with RNGs, many slots still relied on the faithful mechanics using gears and levers. 

1996 Onwards

In 1996, the slots industry reached another milestone when WMS Industries Inc. created the “Reel ‘Em” – the first video slot machine to feature a second screen bonus round. When the bonus round is triggered, a different screen displays a bonus game interface, allowing players to earn additional payouts. This feature brought the slots to greater heights, becoming one of the major money-earners of every casino. It was so popular that it began taking up to 70% of every casino’s available floor space.

The Rise of Online Slots

The development of Internet technology in the mid 90’s prompted the arrival of online casinos. Slots also became available, following roulette and blackjack games online. As it did in land-based casinos, slots quickly became popular online, becoming the bulk of every online casinos’ game selection.



Fast forward to the 2000s. Slots further improved. They also moved from physical casinos and pubs to the online world. RNGs also developed further, turning into something that uses up very little space and memory while making every spin random and fair.

With the development of computer and Internet technologies, many new types of slots and egames like online bingo emerged. Most of them came with interesting themes or unusual layouts and structures, endless variety of symbols, and even innovative and imaginative bonus rounds and special game features. 

The number of slot developers increased, along with over 100 developers of online slots. Although some come with minimal selection of games, there are some giants in the industry like, Habanero, Netent, PG Soft, Real Time Gaming, and CQ9, who also offer an enormous choice. 

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