Triple Diamond Keno

Introduction

Triple Diamond Keno is a little known keno-based game that has been around since 1996. It plays like regular keno, except the ball draw may also uncover diamonds. If three diamonds are found, the player wins three times his bet plus three free games with a tripled multiplier.

Currently, the game is rather dated and difficult to find. I would speculate your odds are best on small cathode ray GameMaker machines. The game is similar in theory to Caveman Keno, but the graphics are not as impressive, which is probably why Triple Diamond Keno is fading off into the sunset.

Rules

Player chooses 2 to 10 numbers from 1 to 80.
The game will choose 20 numbers from 1 to 80.
If the player and game choose the same number, it is said to be a "catch." The more numbers the player catches, the more he wins. Sometimes the game also pays for zero catches.
The game will also appear to hide diamonds among the numbers not chosen by the player. If three of them are uncovered during the draw of the 20 random numbers, then the player will win both of the following.
- Three times his bet.
- Three free games with a 3x multiplier (i.e. all wins in free games are tripled).
If the player gets three diamonds in a free game, then he will win nine times his initiating wager. However, this does not add to the number of free games.
The probability of the three diamonds is exactly 2%. This is determined outside of the draw of the balls.

Analysis

One can use conventional keno math to get the return of the game, before considering the Triple Diamond feature. If this base return of the game is b, then the total return of the game can be defined as 1.18 × b + 0.0708.

The game I noticed at the Green Valley Ranch had two pay tables, according to the denomination bet. Here are both of them. The return of each pay table is in the bottom row.