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Keno Random Number Generator

How Keno Works

Keno is a lottery style game where players select a set of numbers, which are drawn in a way to randomize them. A gambler picks up to 20 different numbers (called “spots”) from between 1 and 80. The more numbers which match (called “catches”), the bigger the payout will be.

Don’t expect to have all twenty of your spots selected. The odds of getting 20 out of 20 numbers are so high that it’s considered virtually impossible, literally in the 1-in-quintillions.

How RNGs Work

Random number generators have been used since the late 1970’s and early 1980’s in electronic gaming machines. Electronic pokie machines contained the first RNGs in casinos. These computer chips allowed the machine to randomize numerals without the need of mechanical pokies reels.

Instead, the software ran an algorithm through the computer chip and produced a result. Each possible outcome was given its own number designation. The possible results with a higher probability were given multiple numbers, while the rarest possibility (the jackpot sequence) was given few, perhaps one, number.

When a random one of these numbers was generated, this was matched against the reel positions corresponding to that number and the result was flashed on the screen. In this way, randomized reel positions were created, allowing the machine to determine whether someone was a winner or loser. This freed game designers to create ever more elaborate game dynamics.

The old mechanical system had only so much room to spare, so only 3 reels could fit in the box and those reels could have only a certain number of icons on them. Bigger boxes had one been used to produce more reels and icons, but they were too big and clunky to be cost-effective. The RNG allowed designers to create 5-reel and even 7-reel games.

The new technology also made possible the progressive jackpot. With all the new innovations in game design, poker machines became the most popular game in casinos and the most profitable game for casino owners. While the pokies were evolving, game design companies began toying around with the idea of applying the new technology to other games.

In time, all would be converted to RNGs for the online casino industry, but the lotto style games were of particular interest to software development people, because of the astronomical mathematics needed to produce some of their results.

Traditional Draw Systems

The traditional game of keno came out of a China’s gambling city of Macau in the mid-19th century. The city was ruled by Portugal at the time, so it appears the lottery game was transplanted to China in 1847 or a few years earlier. 1847 is when the first mention of lotto games in China entered the written record, though gambling legends suggest the game came much earlier (even funding the Great Wall of China).

The earliest sheets used the first 80 characters in a famous Chinese poem known as the Thousand Character Classic. “Characters” are the Chinese equivalent to letters of the alphabet, though their language uses symbols to convey a meaning, not build words. When the game was transplanted to the United States, draws for keno used lottery or bingo style balls painted with these (or other) characters, which were drawn out of a hopper or other randomizing container: either rabbit ear blower, an automated blower called an “AKV”, or a spinning metal ball cage called a hand cage.

In time, the numbers 1 through 80 became standard in Western casinos.

Pay Schedules

The game uses a pay schedule much like you would see on poker machines or video poker games. Each number of catches comes with a different size payout. This payout number is multiplied by the amount of money you wagered. If you bet $2 and the payout says 10, you win $20.

These pay schedules go up to the maximum number of catches, though players can’t expect to win beyond a 15-ball catch. Gamblers need to know you never win back your stake, even if you win.

RNG Design and Keno

Most lottery games in the West use somewhere between 38 and 55 number possibilities, with 6 numbers drawn. Increasing the number options to 80 and having 20 balls increases the possible combinations to astronomical proportions. The odds of hitting all 20 spots is 1 in 3.5 quintillion, a number so far removed from our common everyday experience that it’s impossible to imagine.

With such a high number of possible outcomes, the keno RNG needs to be able to calculate and spit out numbers at a lightning fast rate. Remember back to discussion to the reel positions of pokies and all the possible symbol combinations. Now think of all the possible combinations which have to be counted up in this game and you’ll see why the keno random number generator has to handle a much larger number of calculations. Quintillions of options must be randomized.

Thousands of results are produced every second. When the keno draw occurs, the RNG chooses the number current for that split-second and matches it against the 20 spots chosen for the corresponding number in the sequence. That’s how a keno result is reached with an RNG.

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