Keno History
The game of Keno has been played for many centuries now. 
When the Chinese reached the American mainland during the 19th century, they brought along the game of Keno to remind them of their heritage. The Americans then played the game.
The game Keno was not legalized while most gambling formats were allowed.
A story about horse racing was used to hide the Keno game, the operators mention that the numbers on the Keno system symbolize horses and players are just betting on which “horse” would come in.
Keno gained popularity, the USA government taxed off track betting. This tax hit Keno since it was called “horse race” Keno. Keno it remains one of the most sought after games either in casinos.