Gaming machine and method for a bonus game with increasing payout rate

1. A gaming machine comprising:

a symbol display device configured to variably display and rearrange symbols including a trigger symbol;

a validator configured to validate game media that has been added to the gaming machine and to receive the game media into the gaming machine when the game media is valid; and

a controller programmed to, as a result of a player having wagered game media, execute the processes of:

(a1) executing a normal game by rearranging the symbols on the symbol display device;

(a2) determining whether a trigger condition indicating that a first predetermined number or more of the trigger symbol is rearranged is established in the normal game;

(a3) when the trigger condition is established, executing a free game for a second predetermined number of times as a bonus game;

(a4) each time the free game is executed in the bonus game, determining whether a re-trigger condition indicating that a number of rearranged trigger symbols is smaller than first the predetermined number is rearranged is established; and

(a5) each time the re-trigger condition is established, increasing a payout rate of the free game executed as the bonus game,

wherein the controller:

includes a rank data table in which the number of rearranged trigger symbols is associated with a rank; and

in the process (a5),

calculates a rank corresponding to the number of rearranged trigger symbols with which the re-trigger condition is established, based on the rank data table, and

multiplies the payout rate of the free game executed as the bonus game by the rank.

2. The gaming machine according to claim 1 , wherein,

the controller increases, in the process (a5), the payout rate of the free game executed as the bonus game in accordance with the number of the trigger symbol with which the re-trigger condition is established.

3. The gaming machine according to claim 1 , wherein,

the controller increases, in the process (a5), the number of times of execution of the free game executed as the bonus game by a number which is smaller than the second predetermined number of times.

4. The gaming machine according to claim 1 , wherein,

the controller includes a re-trigger data table in which a combination pattern of the trigger symbol is associated with an additional number of times of execution of the free game which is smaller than the second predetermined number of times, and

in the process (a5),

calculates an additional number of times corresponding to a combination pattern of the trigger symbol with which the re-trigger condition is established, based on the re-trigger data table, and adds the additional number of times to the number of times of execution of the free game.

5. The gaming machine according to claim 1 , further comprising

a symbol data storage which is configured to store symbol data of symbols including the trigger symbol and a wild symbol,

the symbol display device being able to change the type and number of the symbols based on the symbol data, and

the controller executing the bonus game using the symbol display device on which a number of the wild symbol is increased as compared to a number in the normal game, when the trigger condition is established in the process (a3).

6. The gaming machine according to claim 1 , wherein,

the symbol display device includes reels on which the symbols including the trigger symbol are variably displayed and rearranged,

the trigger condition further indicates that a third predetermined number or more of reels on which the trigger symbol is arranged neighbor one another, and

the retrigger condition further indicates that the trigger symbol is rearranged on reels the number of which is smaller than the third predetermined number.

7. A gaming machine comprising:

a symbol data storage configured to store symbol data of symbols including a trigger symbol and a wild symbol;

a symbol display device being able to change the number and type of the symbols using the symbol data and variably displaying and rearranging the symbols;

a validator configured to validate game media that has been added to the gaming machine and to receive the game media into the gaming machine when the game media is valid; and

a controller which includes a re-trigger data table in which a combination pattern of the trigger symbol is associated with an additional number of times of execution of a game which is smaller than a first predetermined number of times and is programmed to, as a result of a player having wagered game media, execute the processes of:

(a1) executing a normal game by rearranging the symbols on the symbol display device;

(a2) determining whether a trigger condition indicating that a second predetermined number or more of the trigger symbol is rearranged is established in the normal game;

(a2-1) when the trigger condition is established, increasing a number of the wild symbol as compared to the normal game;

(a3) when the trigger condition is established, executing a free game for the first predetermined number of times as a bonus game, using the symbol display device on which the number of the wild symbol is increased in the process (a2-1);

(a4) each time the free game is executed in the bonus game, determining whether a re-trigger condition indicating that a number of rearranged trigger symbols is smaller than the second predetermined number is rearranged is established; and

(a5) when the re-trigger condition is established, calculating the additional number of times of execution of the game corresponding to the combination pattern of the trigger symbol with which the re-trigger condition is established, based on the re-trigger data table, adding the additional number of times to the number of times of execution of the free game executed as the bonus game, and increasing a payout rate of the free game executed as the bonus game,

wherein the controller:

includes a rank data table in which the number of rearranged trigger symbols is associated with a rank; and

in the process (a5),

calculates a rank corresponding to the number of rearranged trigger symbols with which the re-trigger condition is established, based on the rank data table, and

multiplies the payout rate of the free game executed as the bonus game by the rank.

8. A gaming machine comprising:

a symbol display device including reels on which symbols including a trigger symbol are variably displayed and rearranged;

a validator configured to validate game media that has been added to the gaming machine and to receive the game media into the gaming machine when the game media is valid; and

a controller programmed to, as a result of a player having wagered game media, execute the processes of:

(a1) executing a normal game by rearranging the symbols on the symbol display device;

(a2) determining whether a trigger condition is established in the normal game;

(a3) when the trigger condition is established, executing a free game for a predetermined number of times as a bonus game;

(a4) each time the free game is executed in the bonus game, determining whether a re-trigger condition is established, an establishment probability of the re-trigger condition being higher than an establishment probability of the trigger condition; and

(a5) when the re-trigger condition is established, increasing a payout rate of the free game executed as the bonus game,

wherein the controller:

includes a rank data table in which a number of rearranged trigger symbols is associated with a rank; and

in the process (a5),

calculates a rank corresponding to the number of rearranged trigger symbols with which the re-trigger condition is established, based on the rank data table, and

multiplies the payout rate of the free game executed as the bonus game by the rank.

9. A game controlling method for a gaming machine including a symbol display device including reels on which symbols including a trigger symbol are variably displayed and rearranged and a validator configured to validate game media that has been added to the gaming machine and to receive the game media into the gaming machine when the game media is valid, the method comprising, as a result of a player having wagered game media:

executing a normal game by rearranging the symbols on the symbol display device;

determining whether a trigger condition indicating that a first predetermined number or more of successive different reels on which the trigger symbol is arranged neighbor one another is established in the normal game;

when the trigger condition is established, executing a free game for a second predetermined number of times as a bonus game;

each time the free game is executed in the bonus game, determining whether a re-trigger condition indicating that the trigger symbol is rearranged on reels the number of which is smaller than the first predetermined number is established; and

when the re-trigger condition is established, increasing a payout rate of the free game executed as the bonus game,

wherein increasing the payout rate includes

calculating a rank corresponding to the number of rearranged trigger symbols with which the re-trigger condition is established, based on a rank data table in which the number of rearranged trigger symbols is associated with a rank, and

multiplying the payout rate of the free game executed as the bonus game by the rank.