Patent ID: 8235799

Claim:
A gaming machine comprising: (i) a display device on which a plurality of symbols are displayed; (ii) a memory for storing data concerning the plurality of symbols to be displayed on the display device; and (iii) a controller; wherein: the plurality of symbols include: one or more first symbols each treated as a symbol for shifting a base game to a feature game; and one or more second symbols each appearing during both of the base game and the feature game, the one or more second symbols each treated as a symbol for shifting the feature game to a next feature game; and the controller is configured to: (a) display a first subset of the plurality of symbols in a display region of the display device during the base game, the first subset including at least one first symbol and at least one second symbol; (b) determine whether to shift the base game to the feature game including: performing the shifting upon detecting a first trigger, the first trigger including a number of the first symbols in the first subset is at least a predetermined number during the base game, and remaining in the base game upon detecting that a number of the first symbols in the first subset is less than the predetermined number and a number of the second symbols within the first subset reaches the predetermined number; (c) display a second subset of the plurality of symbols in the display region of the display device during the feature game, the second subset including at least one first symbol and at least one second symbol; and (d) shift the feature game to the next feature game upon detecting a second trigger, the second trigger including a sum of: a number of the first symbols in the second subset that is less than the predetermined number and a number of the second symbols in the second subset that reaches the predetermined number.