Keno traces its roots back to ancient China, during the Han Dynasty (206 BC – 220 AD). Tradition credits its creation to Cheung Leung, a general who around 200 BC is said to have invented this lottery game to fund his besieged city's defense without raising new taxes. The original game, called "baige piao" (白鸽票, "white pigeon ticket"), used the first 120 characters of the Qianziwen (千字文), the famous "Thousand Character Classic" composed during the Liang Dynasty in the 6th century. Draw results were carried from major cities to remote villages by carrier pigeon — hence the game's evocative name. Some historians claim the revenue generated helped finance the construction of the Great Wall of China, although this assertion remains debated among sinologists.
The baige piao remained a popular game in China for two millennia, evolving across dynasties. Under the Tang Dynasty (618–907), imperial lotteries were commonly used to fund public works. Under the Qing Dynasty (1644–1912), the game became standardized around 80 characters drawn from the Qianziwen, with players typically selecting 10. Macao, a Portuguese trading post since 1557, became a crossroads where Chinese and European gaming traditions intermingled. Governor Isidoro Francisco Guimarães authorized lotteries in 1847, making Macao the first territory to legalize gambling in East Asia.
In the 19th century, the California Gold Rush (1848–1855) attracted tens of thousands of Chinese workers. They brought baige piao with them, quickly renamed "Chinese lottery" by Americans. The 120 Chinese characters were replaced by 80 numbers to make it accessible to English-speaking players. The word "Keno" appeared in the 1860s — its etymology is disputed: some linguists trace it to the French "quine" (five winning numbers in a lottery), inherited from French-speaking settlers in Louisiana; others to the Latin "quini" (five each). In Houston, an operator named Joe Lee organized daily games in Chinatown saloons as early as 1866.
Modern Keno was born in Reno, Nevada, in 1933, following the end of Prohibition and the legalization of gambling. Warren Nelson opened the first "Keno lounge" at the Palace Club, keeping the format of 80 numbers with 20 drawn — the format still in use today. In 1951, the US government imposed a tax on "lotteries"; to avoid it, casinos renamed the game "horse race keno" by associating each number with a fictitious horse. The ruse was short-lived, but the term "race" to describe a Keno draw persists in Las Vegas casino jargon to this day. In 1963, Joe Lyons of the Fremont Casino introduced the first electronic Keno system, replacing the traditional wooden balls with a mechanical random number generator.
The mathematics of Keno are based on hypergeometric combinatorics. With 80 numbers and 20 drawn, the total number of possible combinations is C(80,20) ≈ 3.5 × 10¹⁸ — more than 3.5 billion billion different possible draws. The probability of hitting 10 numbers out of 10 is approximately 1 in 8.9 million (exact formula: C(10,10)×C(70,10)/C(80,20)), comparable to the French Loto. Mathematician Joseph Mazur, in his book "What's Luck Got to Do with It?" (2010), demonstrated that the expected return on casino Keno ranges between 65% and 80% of the amount wagered depending on the pay table — a return-to-player (RTP) rate among the lowest of all casino games, even lower than slot machines (85–98%).
The psychology of Keno fascinates behavioral science researchers. Mark Griffiths, professor at Nottingham Trent University, showed in 2005 that Keno players exhibit a "personal selection bias": 73% believe their "lucky numbers" are more likely to be drawn than random numbers. The illusion of control, described by Ellen Langer (Harvard, 1975), is particularly pronounced in Keno because the player actively chooses their numbers, unlike a passive lottery. The work of Daniel Kahneman and Amos Tversky on the availability heuristic (1973) also explains why players overestimate their chances: the rare big wins are widely publicized, while the millions of losing tickets remain invisible.
In France, the Française des Jeux (FDJ) launched Keno on September 25, 1993, under the name "Keno Gagnant à Vie" (Keno Winner for Life). The concept innovated by offering a life annuity of 5,000 euros per month rather than a single jackpot. In 2018, the FDJ modernized the format: players choose 2 to 10 numbers out of 70 (instead of 80), with daily draws at 1 PM and 9 PM. The maximum prize became 2 million euros or 20,000 euros per month for life. In the United States, Keno generates over 1.1 billion dollars in annual revenue in Nevada casinos. In Australia, "Keno Classic" is broadcast live in more than 3,000 pubs and clubs, with a draw every 3 minutes — the fastest draw rate in the world. Digital Keno, which emerged with online gaming sites in the 2000s, now accounts for 35% of the global Keno market, estimated at 4.2 billion dollars in 2024 according to Grand View Research.