Keno started out using 120 Chinese characters. Before the game left China, that number was reduced to 90. The game came to America with the wave of Chinese immigrants in the 19th century. These were mostly the Chinese railroad workers of folklore. About this time the game was reduced to 80 Chinese characters.
Although illegal, keno thrived among Chinese immigrants, especially around big cities like San Francisco. It became known as the Chinese lottery. English speaking Americans became interested in the game, but had difficulty differentiating the Chinese characters used in the game. Around the beginning of the 20th century, keno operators replaced the Chinese characters with Arabic numbers to entice more players.
Although Nevada legalized most forms of gambling in 1931, the legislature did not legalize lottery. And the Chinese lottery was definitely a lottery. To get around this nuisance, operators simply changed the name to Race Horse Keno. Each number was deemed to be a horse. Today many keno operations still call their games "races". When the U.S. Government passed a law taxing off track betting, the name was once again changed, this time to just Keno.
In 1963 the aggregate keno payout limit in Nevada was $25,000. In 1979 it was changed to $50,000. In 1989 the Nevada Gaming Commission eliminated the cap, and casinos are now free to set their aggregate limits as they wish.
The next time you're in your favorite keno lounge crumpling your loosing ticket, let your mind wonder back 3000 years to the Han Dynasty. You're not the first to be lured by this game, and you certainly will not be the last!