Patent ID: 7172505

Claim:
A method for qualifying a player to play a bonus game from play of a casino base game, play of the casino base game providing a reel spin outcome on a plurality of reels occurring in response to a wager from the player, the casino base game paying the player an award for a winning combination of symbols in the reel spin outcome, and play of the bonus game occurring with a bonus-game occurrence probability during play of the casino base game, the method for qualifying comprising: providing in the play of the casino base game in response to the wager a first stage qualifying arrangement of at least one bonus trigger symbol in the plurality of reels of the reel spin outcome, the first stage qualifying arrangement having a first probability of occurrence during play of the casino base game; each at least one bonus trigger symbol having randomly associated therewith either a non-qualifying bonus symbol or a bonus qualifying symbol; selecting, by the player in the play of the casino base game, at least one bonus trigger symbol in the first stage qualifying arrangement only in response to when the first stage qualifying arrangement occurs in the provided reel spin outcome; in response to the aforesaid selecting, the casino base game then causing each said selected bonus trigger symbol in the provided reel spin outcome to turn from the selected trigger symbol to reveal to the player, on said plurality of reels in said reel spin outcome of the casino base game, either the associated non-qualifying bonus symbol or the associated bonus qualifying symbol; only the revealing of at least one said associated bonus qualifying symbol in the reel spin outcome providing a second stage qualifying arrangement in the play of the casino base game; not providing the second stage qualifying arrangement in the play of the casino base game, and not providing any award for said selection, at least when each said selected trigger bonus symbol reveals to the player an associated non-qualifying bonus symbol; the second stage qualifying arrangement having a second probability of occurrence during play of the casino base game, said bonus-game occurrence probability being a product of said first probability of occurrence and said second probability of occurrence, said first probability of occurrence and said second probability of occurrence each being less than one, wherein said first probability of occurrence is less than said second probability of occurrence; commencing play, by the player, of the bonus game to receive a bonus award only in response to providing said second stage qualifying arrangement during play of the casino base game.