A slot machine (American English), poker machine (Australian English), or fruit machine (British English) is a certain type of casino game. Traditional slot machines are coin-operated machines with three or more reels, which spin when a lever on the side of the machine is pulled. The machines include a currency detector that validates the coin or money inserted to play. (The slot machine is also known informally as a one-armed bandit because of its traditional appearance and its ability to leave the gamer penniless.) The machine typically pays off based on patterns of symbols visible on the front of the machine when it stops. Modern computer technology has resulted in many variations on the slot machine concept. Today, slot machines are the most popular gambling method in casinos and constitute about 70% of the average casino’s income.
Sittman and Pitt of Brooklyn, New York developed a gambling machine in 1891 that could be considered a precursor to the modern slot machine. It contained 5 drums holding a total of 50 card faces and was based on poker. This machine proved extremely popular and soon there was hardly a bar in the city that didn’t have one or more of the machines bar-side. Players would insert a nickel and press a lever, which would spin the drums and the cards they held, the player hoping for a good poker hand. There was no direct payout mechanism, so a pair of Kings might get you a free beer, whereas a Royal Flush could payout cigars or drinks, the prizes wholly dependent on what was on offer at the local establishment. In order to make the odds better for the house, two cards were typically removed from the “deck”: The Ten of Spades and the Jack of Hearts, which cut the odds of winning a Royal Flush by half. The drums could also be re-arranged to further reduce a player’s chance of winning.
The first “one-armed bandit” was invented in 1887 by Charles Fey of San Francisco, California, who devised a much simpler automatic mechanism. Due to the vast number of possible wins with the original poker card-based game, it proved practically impossible to come up with a way to make a machine capable of making an automatic pay-out for all possible winning combinations. Charles Fey devised a machine with three spinning reels containing a total of five symbols – horseshoes, diamonds, spades, hearts and a Liberty Bell, which also gave the machine its name. By replacing ten cards with five symbols and using three reels instead of five drums, the complexity of reading a win was considerably reduced, allowing Fey to devise an effective automatic payout mechanism. Three bells in a row produced the biggest payoff, ten nickels. Liberty Bell was a huge success and spawned a thriving mechanical gaming device industry. Even when the use of these gambling devices was banned in his home State after a few years, Fey still couldn’t keep up with demand for the game elsewhere.
Another early machine gave out winning in the form of fruit flavored chewing gums with pictures of the flavors as symbols on the reels. The popular cherry and melon symbols derive from this machine. The “BAR” symbol now common in slot machines was derived from an early logo of the Bell-Fruit Gum Company. In 1964, Bally developed the first fully electromechanical slot machine called Money Honey
A person playing a slot machine purchases the right to play by inserting coins, cash, or in newer machines, a bar-coded paper ticket (known as “ticket in/ticket out” machines), into a designated slot on the machine. The machine is then activated by means of a lever or button, or on newer machines, by pressing a touchscreen on its face. The game itself may or may not involve skill on the player’s part — or it may create the illusion of involving skill without actually being anything else than a game of chance. The object of the game is to win money from the machine. The game usually involves matching symbols, either on mechanical reels that spin and stop to reveal one or several symbols, or on a video screen. The symbols are usually brightly colored and easily recognizable, such as images of fruits, and simple shapes such as bells, diamonds, or hearts.
Most games have a variety of winning combinations of symbols, often posted on the face of the machine. If a player matches a combination according to the rules of the game, the slot machine pays the player cash or some other sort of value, such as extra games. There are many different kinds of gambling slot machines in places such as Las Vegas. Some of the most popular are the video poker machines, in which players hope to obtain a set of symbols corresponding to a winning poker hand. There are standard 5-card draw machines, all the way up to 100-play machines, where you can play 100 hands at a time.
Becoming more popular now are the 9 line slots. Usually these are themed slots, with graphics and music based on popular entertainers or TV programs (The Addams Family, I Dream of Jeannie, etc.) with a bonus round. Most accept variable amounts of credit to play with 1 to 5 credits per line being typical. The higher the amount bet, the higher the payout will be. Of course, there are the standard 3 – 5-reel slot machines, of various types. These are the typical “one-armed bandits”.
One of the main differences between video slots and reel slots is in the way payouts are calculated. With reel slots, the only way to win the maximum jackpot is to play the maximum number of coins (usually 3, sometimes 4, or even 5 coins per spin). With video slots, the fixed payout values are multiplied by the number of coins per line that are being bet. In other words: on a reel slot, it is to the player’s advantage to play with the maximum number of coins available. On video slots, it is recommended to play as many individual lines as possible, but there is no benefit to the player in betting more than one credit per line with regards to calculating the payout amounts. (There are some isolated cases where a video slot machine requires the maximum number of credits per spin to be inserted to win the largest payout, but those are the exception.) An example: On the “Wheel of Fortune” reel slot, the player must play 3 coins per spin to be eligible to trigger the bonus round and possibly win the jackpot. On the Wheel of Fortune video slot, the chances of triggering the bonus round or winning the maximum jackpot are exactly the same regardless of the number of coins bet on each line.
Larger casinos offer slot machines with denominations from $.01 (penny slots) all the way up to $100.00 or more per credit. Large denomination slot machines are usually cordoned off from the rest of the casino into a “High Limit” area, often with a separate team of hosts to cater to the needs of the high-rollers who play there. Slot machines common in casinos at this time are more complicated. Most allow players to accept their winnings as credits, which may be “spent” on additional spins.