Patent Publication Number: US-2009239639-A1

Title: Gaming Machine Capable Of Multiplying Award By Rearranging Specific Symbols Consecutively In A Free Game

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. Provisional Application No. 61/038,963, filed Mar. 24, 2008, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to gaming machines that performs slot games in which each of a plurality of symbols are rearranged and free games in which a multiplier can be changed. 
     2. Related Art 
     It is known that conventional slot machines start a game when a predetermined amount of credit is bet, then start to rotate a plurality of reels on which a plurality of symbols is depicted, and stop the rotation after a predetermined period of time elapses. As a result, a certain award is provided to a player based on a stationary combination of symbols. 
     U.S. Pat. No. 7,338,370 discloses display screens of a slot machine for entering a bonus game from a base game. In the basic game, a multiplier of a bonus game award, which is multiplied for an amount of coins a player bet, is selectably determined and displayed in a display screen. Furthermore, during the bonus game, when the player selects one bonus symbol among a plurality of bonus symbols, a bonus game award corresponding to the selected bonus symbol is displayed. Moreover, an amount of bets carried over from the basic game and the multiplier selected based on the carry-over bet amount are displayed. In addition, the bonus game award and a total award, that is, the bonus game award multiplied by the multiplier are displayed, whereby the player can recognize the total amount to be paid out in the bonus game. In other words, the multiplier for the total award to be paid out in the bonus game is gradually determined based on the base game. 
     In such a slot game as described above, a bonus game depends somewhat on a bet amount in a base game and a multiplier selected based on the bet amount in the base game. Since it is difficult for a player to calculate a total award of a bonus game, a display screen for displaying guidance and the like is required. This interrupts a smooth flow of switching from a base game to a bonus game. In this way, the progress of a bonus game is far from speedy and exciting due to an adverse effect of excessively preceding expectation produced by the player. 
     SUMMARY OF THE INVENTION 
     The present invention has an object to provide a gaming machine that can provide a player-friendly game with speed and excitement, and which can change a multiplier for the game, without interruption of the flow of the game. 
     Furthermore, the present invention has an object to provide a gaming machine which can further improve entertainment properties. 
     In the first aspect of the present invention, a gaming machine includes: 
     a display having a plurality of symbol display regions and displaying a symbol to be rearranged in each of the symbol display regions for each round of a game; 
     an input device for starting a basic game in which an award is provided based on an arrangement of symbols rearranged in a symbol display area for providing an award, the symbol display area including the plurality of symbol display regions on the display, a type of the award being determined according to one of a number of identical symbols and a combination of symbols lying along an active line; and 
     a controller configured to execute the processing including: 
     (a) starting a basic game, and after performing at least one round of the basic game, switching the basic game to a free game; 
     (b) rearranging a predetermined symbol randomly in each region of the symbol display area for providing an award on the display for each round of the free game; and 
     (c) if an arrangement of symbols rearranged in the symbol display area for providing an award matches an arrangement entitled to a predetermined award after a plurality of rounds of the free game, increasing an amount of payout for the predetermined award according to a number of consecutive rounds previously played of the free game in each of which a specific symbol is rearranged in the symbol display area for providing an award. 
     In the second aspect of the present invention, a gaming machine includes: 
     a display having a plurality of symbol display regions and displaying a symbol to be rearranged in each of the symbol display regions for each round of a game; 
     an input device for starting a basic game in which an award is provided based on an arrangement of symbols rearranged in a symbol display area for providing an award, the symbol display area including the plurality of symbol display regions on the display, a type of the award being determined according to one of a number of identical symbols and a combination of symbols lying along an active line; and 
     a controller configured to execute the processing including: 
     (a) starting a basic game, and after performing at least one round of the basic game, switching the basic game to a free game; 
     (b) rearranging a predetermined symbol randomly in each region of the symbol display area for providing an award on the display for each round of the free game; 
     (c) at the end of each round of the free game, updating and storing a number of consecutive rounds of the free game in each of which a specific symbol is rearranged in the symbol display area for providing an award; and 
     (d) if the specific symbol is not rearranged in the symbol display area for providing an award in one round of the free game, providing an award based on the number of consecutive rounds of the free game in each of which the specific symbol is rearranged, the number being stored in the previous round of the free game. 
     In the third aspect of the present invention, a gaming machine includes: 
     a display having a plurality of symbol display regions and displaying a symbol to be rearranged in each of the symbol display regions for each round of a game; 
     an input device for starting a basic game in which an award is provided based on an arrangement of the symbols rearranged in a symbol display area for providing an award, the symbol display area including the plurality of symbol display regions on the display, a type of the award being determined according to one of a number of identical symbols and a combination of symbols lying along an active line; and 
     a controller configured to execute the processing including: 
     (a) starting a basic game, and after performing at least one round of the basic game, switching the basic game to a free game; 
     (b) rearranging a predetermined symbol randomly in each region of the symbol display area for providing an award on the display for each round of the free game; 
     (c) at the end of each round of the free game, updating and storing a number of consecutive rounds of the free game in each of which a specific symbol is rearranged in the symbol display area for providing an award; and 
     (d) if the specific symbol is not rearranged in the symbol display area for providing an award in one round of the free game, providing an award based on a payout table that correlates a payout with the number of consecutive rounds of the free game in each of which the specific symbol is rearranged, the number being stored in the previous round of the free game. 
     In the fourth aspect of the present invention, a gaming machine includes: 
     a display having a plurality of symbol display regions and displaying a symbol to be rearranged in each of the symbol display regions for each round of a game; 
     an input device for starting a basic game in which an award is provided based on an arrangement of symbols rearranged in a symbol display area for providing an award, the symbol display area including the plurality of symbol display regions on the display, a type of the award being determined according to one of a number of identical symbols and a combination of symbols lying along an active line; and 
     a controller configured to execute the processing including: 
     (a) starting a basic game, and after performing at least one round of the basic game, switching the basic game to a free game; 
     (b) rearranging a predetermined symbol randomly in each region of the symbol display area for providing an award on the display for each round of the free game; 
     (c) at the end of each round of the free game, updating and storing a number of consecutive rounds of the free game in each of which a specific symbol is rearranged in the symbol display area for providing an award; and 
     (d) if the specific symbol is not rearranged in the symbol display area for providing an award in one round of the free game, increasing an amount of an award determined based on an arrangement of symbols displayed in the symbol area for providing an award, which has triggered a switch from the basic game to the free game in processing (a), according to the number of consecutive rounds of the free game, which is stored in the previous round of the free game in which the specific symbol is rearranged, and providing the increased amount of the award. 
     In the fifth aspect of the present invention, a gaming machine includes: 
     a display having a plurality of symbol display regions and displaying a symbol to be rearranged in each of the symbol display regions for each round of a game; 
     an input device for starting a basic game in which an award is provided based on an arrangement of symbols rearranged in a symbol display area for providing an award, the symbol display area including the plurality of symbol display regions on the display, a type of the award being determined according to one of a number of identical symbols and a combination of symbols lying along an active line; and 
     a controller configured to execute the processing including: 
     (a) starting a basic game, and after performing at least one round of the basic game, switching the basic game to a free game; 
     (b) rearranging a predetermined symbol randomly in each region of the symbol display area for providing an award on the display for each round of the free game; 
     (c) at the end of each round of the free game, updating and storing a number of consecutive rounds of the free game in each of which a specific symbol is rearranged in the symbol display area for providing an award; 
     (d) if an arrangement of the symbols displayed in the symbol display area for providing an award matches an arrangement entitled to an award as a result of a round of the free game, providing the award according to the number of consecutive rounds of the free game cumulatively stored in processing (c) in each of which the specific symbol is rearranged; and 
     (e) if the specific symbol is not rearranged in the symbol display area for providing an award, resetting the number of consecutive rounds of the free game in processing (c) in each of which the specific symbol is rearranged, and performing subsequent rounds of the free game. 
     According to abovementioned each aspect of the present invention, a player advances a game to a free game from a basic game, and in a case where the specific symbol is consecutively rearranged in the symbol display area for providing an award during the free game, an award is increased (by addition or multiplication) based on the number of consecutive rounds of the free game in each of which the specific symbol is rearranged. Such a configuration makes the game, in which the specific symbol and the symbol display regions (symbol display positions) are visually related to the award (increase of the award) directly, easier to operate for a player. Accordingly, the gaming machine provides a game with speedy and exciting progress, allowing the player to feel more excited. Since the player is allowed to select the specific symbol, the player may feel further excited. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flow chart showing a flow of a game executed in a gaming machine according to an embodiment of the present invention; 
         FIG. 2  is a perspective view showing an appearance of the gaming machine according to the embodiment of the present invention; 
         FIG. 3  is a plan view showing an enlarged display area of the gaming machine according to the embodiment of the present invention; 
         FIG. 4  is a block diagram illustrating a controller of the gaming machine according to the embodiment of the present invention; 
         FIG. 5  is a block diagram illustrating a display/input controller of the gaming machine according to the embodiment of the present invention; 
         FIG. 6  is a flow chart showing mainly a flow of basic game processing of the gaming machine according to the embodiment of the present invention; 
         FIGS. 7 and 8  are flow charts each showing an example of a portion of processing in  FIG. 6 ; 
         FIG. 9  is a payout table related to a free game according to the embodiment of the present invention; and 
         FIGS. 10 and 11  are examples each depicting a display screen of a rendered image of a game performed by the gaming machine according to the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The gaming machine according to the present invention is hereinafter described in detail with reference to attached drawings. The present embodiments may preferably, but not necessarily, be applied to a gaming machine such as a slot game. An example of such a gaming machine includes a gaming machine that has an image displaying device such as a liquid crystal display and that advances a game while displaying images of various kinds of symbols on the image displaying device. 
       FIG. 1  is a flow chart showing a flow of a game executed in a gaming machine according to an embodiment of the present invention. As shown in  FIG. 1 , a CPU  106  (refer to  FIG. 4 ) starts a basic game (Step S 100 ), displays dynamically a set of symbols (Step S 200 ), determines symbols to be rearranged (Step S 300 ), and rearranges the symbols (Step S 400 ), the details of which will be described later. Next, the CPU  106  determines whether the rearranged symbols match a combination for allowing a game to advance to a free game, and in a case where the CPU  106  determines an occurrence of matching, the CPU  106  starts a free game (Step S 600 ). The CPU  106  rearranges specific symbols consecutively over a plurality of free games (Step S 700 ), and provides an award based on the number of consecutive rounds of the free game in each of which the specific symbol is rearranged (Step S 800 ). 
       FIG. 2  is a perspective view showing an appearance of the gaming machine according to the embodiment of the present invention. 
     A gaming machine  10  includes a cabinet  20 . The cabinet  20  has a structure in which the face facing a player is open. The cabinet  20  contains various components, including a game controller  100  (refer to  FIG. 4 ) for electrically controlling the gaming machine  10  and a hopper  44  (refer to  FIG. 4 ) for controlling the insertion, storage, and payout of coins (game media), and the like. The game medium is not restricted to coins. In addition, examples of such game media include medals, tokens, electronic money, or electronic value information (credit) having the same value. 
     A liquid crystal display  30  is provided substantially at the center in a front surface of the cabinet  20 . The liquid crystal display  30  realizes a display device for displaying various kinds of images related to a game including rendered images and the like. The gaming machine  10  includes an image display device such as the liquid crystal display  30 , and advances the game while displaying various kinds of symbol images on the image display device. 
     The liquid crystal display  30  includes symbol display regions  301  to  315  of a plurality of divisions (refer to  FIG. 3 ), and repeatedly displays for each game rearrangement of a plurality of kinds of symbols in a symbol display area for providing an award that is formed by the symbol display regions  301  to  315 . The symbol display regions  301  to  315  are configured with video reels for displaying a plurality of virtual reels, for example. It should be noted that the term “video reel” as used here represents a device for displaying a reel on the liquid crystal display  30  in a form of an image instead of mechanical reel. In the present embodiment, fifteen video reels are displayed on the liquid crystal display  30 . In other words, there are provided the symbol display regions ( 301  to  315 ) of fifteen divisions. 
     A start switch  25 , which is one input device, is provided on an operation unit  21  placed below the liquid crystal display  30 . Upon operation of the start switch  25 , a game is started, in which an award is provided corresponding to a number of identical symbols (of the same kind) rearranged in the symbol display area for providing an award that is formed by the symbol display regions  301  to  315 . Other rearrangement patterns for providing an award may include forming a combination of symbols along one of active lines such as L 1  to L 5  as shown in  FIG. 3 . In the present embodiment, the rearrangement pattern presented with a combination of symbols along an active line is set as a trigger for switching a game to a free game, for example. 
     Another liquid crystal display  40  may be further provided above the liquid crystal display  30 . The liquid crystal display  40  can be utilized as a sub display for displaying game rules, a demonstration screen and the like. Sound transmitting openings  29   a  and  29   b , which are provided near the upper portion of the cabinet  20 , transmit sound effects, generated by speakers  41  (refer to  FIG. 4 ) contained in the cabinet  20 , to the outside of the cabinet  20 . The sound transmission openings  29   a  and  29   b  generate sound effects and the like in accordance with the progress of the game. Decorative lamps  42   a  and  42   b  are disposed on both right and left sides substantially in the center of the gaming machine  10  and emit light in accordance with the progress of the game. 
     On a substantially flat operation unit  21  disposed at a lower portion of the liquid crystal display  30 , a coin insertion slot  22 , a bet switch  23 , and a spin repeat bet switch  24  are provided, besides the start switch  25 . The bet switch  23  selects an amount of coins to be bet for a game among a plurality of coins inserted from the coin insertion slot  22 . The spin repeat bet switch  24  starts a game without changing the amount of coins to be bet from the amount of coins bet in a previous game. Such arrangements allow a player to set the amount of coins to be bet for a group of symbols to be formed on activated lines in response to a pushing operation of the bet switch  23  or the spin repeat bet switch  24 . The start switch  25  accepts a starting operation of a game by a player for each game. Triggered by a pressing operation applied to one of the start switch  25  and the spin repeat bet switch  24 , the liquid crystal display  30  displays a display of a dynamic image indicating the plurality of the symbol display regions  301  to  315 . 
     A cash out switch  26  is provided near the coin insertion slot  22  on the operation unit  21 . Upon a pushing operation on the cash out switch  26  by a player, inserted coins are discharged through a coin payout opening  27  provided at a lower portion of the front face of the cabinet  20 . The coins thus discharged are retained in a coin tray  28 . 
       FIG. 3  is an enlarged display area of the liquid crystal display  30  of the gaming machine  10 . The symbol display regions  301  to  315  included in such a display area form a matrix of three rows and five columns, which are also called symbol display blocks and symbol display positions. Fifteen video reels are provided to the symbol display regions  301  to  315 , respectively. 
     A payout amount display unit  48 , a bet amount display unit  50 , and a credit amount display unit  49  are displayed in this order from the left side on the upper portion of the liquid crystal display  30 . The payout display  48  displays a payout amount of coins, in a case where at least a predetermined number of identical symbols for providing an award is arranged, when symbols are dynamically displayed and rearranged in the symbol display area for providing an award that is formed by the symbol display regions  301  to  315 , for example. The credit amount display unit  49  displays the credit amount of coins stored in the gaming machine  10 . The bet amount display unit  50  displays a bet number, which is the amount of coins being bet. 
       FIG. 4  is a block diagram showing the electrical configuration of the game controller  100  of the gaming machine  10 . The controller  100  of the gaming machine  10  is a microcomputer, and includes an interface circuit group  102 , a CPU  106 , a ROM  108 , a RAM  110 , a communication interface circuit  111 , a random number generator  112 , a speaker driving circuit  122 , a hopper driving circuit  124 , a lamp driving circuit  126 , and a display/input controller  140 . These components mentioned above are connected with an input/output bus  104 . 
     The input/output bus  104  transmits the input/output of data signals or address signals to and from the CPU  106 . The start switch  25  is electrically connected with the interface circuit group  102 . A start signal generated by the start switch  25  is converted into a predetermined form of signal in the interface circuit group  102  to be supplied to the input/output bus  104 . 
     The bet switch  23 , the spin repeat bet switch  24 , and the cash out switch  26  are also connected with the interface circuit group  102 . Each of the switching signals output from these switches  23 ,  24 , and  26  is also supplied to the interface circuit group  102 , and is converted into a predetermined form of signal by the interface circuit group  102  to be supplied to the input/output bus  104 . 
     A coin sensor  43  is also electrically connected with the interface circuit group  102 . The coin sensor  43  detects coins inserted into the coin insertion slot  22  and is disposed at an appropriate position relative to the coin insertion slot  22 . A sensing signal output from the coin sensor  43  is also supplied to the interface circuit group  102 , and is converted into a predetermined form of signal by the interface circuit group  102 , to be supplied to the input/output bus  104 . 
     Upon acceptance of a start operation of a game via the start switch  25 , the CPU  106  reads a game program and performs the game. The game program causes the liquid crystal display  30  to start to dynamically display a set of symbols by way of a video reel in each of the symbol display regions  301  to  315  by which the symbol display area for providing an award is formed, via the display/input controller  140 , and subsequently rearranges the set of symbols. In a case where there is at least the predetermined number of identical symbols among all the rearranged symbols, the program is configured so as to instruct payout of coins corresponding to the number of identical symbols. 
     The ROM  108  stores a control program for centrally controlling the gaming machine  10 , a program for executing routines shown in  FIGS. 6 and 7 , or  FIGS. 6 and 8  (hereinafter referred to as a “routine program”), initial data for executing the control program, and various data tables used for determining processing. The routine program includes the abovementioned game program. The data tables shown in  FIG. 9  and the like are examples of data tables. The RAM  110  temporarily stores flags, variables, and the like used for the control program. 
     The game program includes a program for determining symbols to be rearranged. This program determines fifteen symbols to be rearranged in the symbol display regions  301  to  315 , respectively. The program includes symbol weighting data that corresponds to each of a plurality of kinds of payout ratios (e.g., 80%, 84%, and 88%). The symbol weighting data indicates the correlation between a symbol and one or a plurality of random numbers in a predetermined number range (0 to 256) for each of the fifteen video reels. A payout ratio is determined based on data related to setting of payout ratios stored in the ROM  108 . The rearrangement of symbols is determined based on the symbol weighting data corresponding to the payout ratio. 
     The communication interface circuit  111  communicates with a server and a central controller via various kinds of communication networks, such as a LAN. 
     A random number generator  112  generates random numbers lying in a predetermined range of “0” to “65535” (two to the sixteenth power minus one), for example. Alternatively, the CPU  106  may generate a random number by computation. 
     The speaker driving circuit  122  drives the speakers  41 . The CPU  106  reads sound data stored in the ROM  108  and transmits the sound data thus read to the speaker driving circuit  122  via the input/output bus  104 . In this way, the speakers  41  generate predetermined sound effects. 
     The hopper driving circuit  124  drives the hopper  44 . The CPU  106  outputs a driving signal to the hopper driving circuit  124  via the input/output bus  104  in response to receiving a cash out signal from the cash out switch  26 . Accordingly, the hopper  44  pays out an amount of coins equivalent to the current amount of remaining credits, which is stored in a predetermined memory area of the RAM  110 . 
     Alternatively, payout of coins may be performed by way of storing credit data in a data card and the like, instead of using physical coins. In other words, the player may carry a card which serves as a recording medium, and store the data related to the credit by inserting the card into the gaming machine  10 . 
     The lamp driving circuit  126  drives the decorative lamps  42   a  and  42   b . The CPU  106  transmits the signal for driving the lamps according to predetermined conditions based on the program stored in the ROM  108 , to the lamp driving circuit  126 . Thus, the decorative lamps  42   a  and  42   b  blink and the like. 
     The display/input controller  140  generates a signal for driving the liquid crystal displays  30  and  40  according to an image display instruction. The CPU  106  generates an image display instruction according to the status and outcome of a game, and outputs the image display instruction thus generated to the display/input controller  140  via the input/output bus  104 . Upon reception of the image display instruction from the CPU  106 , the display/input controller  140  generates a driving signal for driving the liquid crystal displays  30  and  40  according to the image display instruction thus input, and outputs the driving signal thus generated to the liquid crystal displays  30  and  40 . Consequently, a predetermined image is displayed on the liquid crystal displays  30  and  40 . The display/input controller  140  transmits the signal input via the touch panel  32  provided on the liquid crystal display  30  to the CPU  106  via the input/output bus  104  in the form of an input signal. In addition, the image display instruction includes instructions for the payout display unit  48 , the credit amount display unit  49 , and the bet amount display unit  50 . 
       FIG. 5  is a block diagram showing the electrical configuration of the display/input controller  140  of the gaming machine  10 . The display/input controller  140  of the gaming machine  10  is a sub-microcomputer which executes image display processing and controls input from the touch panel  32 . The display/input controller  140  includes an interface circuit  142 , a CPU  146 , a ROM  148 , a RAM  150 , a VDP  152 , a video RAM  154 , a ROM  156  for storing image data, a driving circuit  158 , and a touch panel controlling circuit  160 . These components are connected with an input/output bus  144 . 
     An image display instruction output from the CPU  106  of the game controller  100  is supplied to the input/output bus  144  via the interface circuit  142 . The input/output bus  144  inputs and outputs data signals and address signals to and from the CPU  146 . 
     The ROM  148  stores a display control program for generating a driving signal to be supplied to the liquid crystal displays  30  and  40  according to the image display instruction from the CPU  106  of the game controller  100 . The RAM  150  stores flags and variables used for the display control program. 
     The VDP  152  includes a so-called sprite circuit, a screen circuit, a palette circuit, and the like, and performs various kinds of processing for displaying images on the liquid crystal displays  30  and  40 . The video RAM  154  and the image data ROM  156  are connected to the VDP  152 . The video RAM  154  stores image data based on the image display instructions from the CPU  106  of the game controller  100 . The image data ROM  156  stores various kinds of image data including the abovementioned rendered image data. The driving circuit  158  for outputting a driving signal to drive the liquid crystal displays  30  and  40  is connected to the VDP  152 . 
     The CPU  104  reads and executes the display control program stored in the ROM  148 , and instructs the video RAM  154  to store image data to be displayed on the liquid crystal displays  30  and  40  according to the image display instruction from the CPU  106  of the game controller  100 . The image display instruction includes various kinds of instructions including an instruction for displaying the abovementioned rendered image and the like. 
     The image data ROM  156  stores various kinds of image data including the image data for the rendered image and the like. The touch panel control circuit  160  transmits a received input signal via the touch panel  32  provided on the liquid crystal display  30 , to the CPU  106  via the input/output bus  144  in the form of an input signal. 
       FIG. 6  is a flow chart showing processing mainly for a basic game of the gaming machine  10  executed by the game controller  100  of the gaming machine  10 . If one routine shown in  FIG. 6  is thoroughly performed, it will result in a unit game. A description is provided with reference to  FIGS. 3 to 5 . 
     It is supposed that the gaming machine  10  is activated in advance, and that the variables used in the CPU  106  of the controller  100  are initialized to predetermined values, whereby the gaming machine  10  is in normal operation. 
     Firstly, the CPU  106  of the game controller  100  determines whether there remains a certain amount of credit which is equivalent to a remaining amount of coins a player has inserted (Step S 1 ). More specifically, the CPU  106  reads a credit amount C stored in the RAM  110 , and executes a processing based on the credit amount C thus read. In a case where the credit amount C is “0” (“NO” in Step  51 ), the CPU  106  terminates the routine without any processing since a game cannot be allowed to start. On the other hand, in a case where the credit amount C is at least “1” (“YES” in Step  51 ), the CPU  106  determines that there are credits remaining, and advances the processing to Step S 2 . 
     In Step S 2 , the CPU  106  determines whether a pushing operation has been executed on a spin repeat bet switch  24 . When the spin repeat bet switch  24  has been pushed, and accordingly, an operation signal from the spin repeat switch  24  has been input to the CPU  106  (“YES” in Step S 2 ), the CPU  106  advances the processing to Step S 13 . On the other hand, in a case where the CPU  106  receives no operation signal from the spin repeat bet switch  24  during a predetermined period of time (“NO” in Step S 2 ), the CPU  106  determines that the spin repeat bet switch  24  has not been pushed, and advances the processing to Step S 3 . 
     In Step S 3 , the CPU  106  sets game conditions. More specifically, the CPU  106  determines the amount of coins to be bet for a unit game based on the operation of the bet switch  23 . Here, the CPU  106  receives an operation signal delivered in response to the operation of the bet switch  23 , and based on the number of times the CPU  106  has received the signal, the CPU  106  stores a bet amount in a predetermined memory area of the RAM  110 . The CPU  106  reads a credit amount C stored in a predetermined area of RAM  110 , subtracts the abovementioned bet amount from the credit amount C thus read, and stores the resulting value in a predetermined memory area of the RAM  110 . Subsequently, the CPU  106  advances the processing to Step S 4 . 
     In the Step S 4 , the CPU  106  determines whether the start switch  25  has been activated, and stands by until the start switch  25  is operated. Upon the start switch  25  being operated, and accordingly, upon the CPU  106  receiving an operation signal from the start switch  25  (“YES” in Step S 4 ), the CPU  106  determines that the start switch  25  has been operated, and advances the processing to Step S 5 . 
     On the other hand, in Step S 13 , the CPU determines whether the credit amount C is equal to or greater than the bet amount in a previous game. In other words, the CPU  106  determines whether the CPU  106  can start a game in response to a pushing operation performed on the spin repeat bet switch  24 . More specifically, when the spin repeat bet switch  24  has been pushed and accordingly the CPU  106  has received an operation signal from the spin repeat bet switch  24 , the CPU  106  reads the credit amount C and the bet amount in a previous game from the RAM  110 , and executes processing based on whether the credit amount C is equal to or greater than the bet amount in the previous game. In a case where the CPU  106  determines that the credit amount C is less than the bet amount in the previous game (“NO” in Step S 13 ), the CPU  106  terminates the routine without executing any processing, since the game is not allowed to start. On the other hand, in a case where the CPU  106  determines that the credit amount C is equal to or greater than the bet amount in the previous game (“YES” in Step S 13 ), the CPU  106  subtracts the bet amount in the previous game from the credit amount C, and stores the resulting value in a predetermined area of the RAM  110 . Subsequently, the CPU  106  advances the processing to Step S 5 . 
     In Step S 5 , the CPU  106  executes processing for determining symbols to be rearranged. A detailed description of this processing is provided below. 
     Firstly, the CPU  106  extracts a random number from the random number generator  112  and selects a random number for each of the fifteen video reels in a range of random numbers 0 to 255. Next, the CPU  106  reads data for setting payout ratios from the ROM  108  and stores the data in the RAM  110 , refers to data for weighting symbols correlated with the data for setting payout ratios, and determines a symbol to be rearranged in each of the symbol display regions  301  to  315  corresponding to the fifteen video reels, based on the fifteen random numbers thus selected. In the present embodiment, in a case where at least five identical symbols (of the same kind) are rearranged in the symbol display regions  301  to  315 , the CPU  106  is configured so as to provide an award corresponding to the rearranged symbols. 
     Following the determination of symbols to be rearranged, the CPU  106  determines whether at least a predetermined number (five) of identical symbols entitled to an award is to be rearranged during the rearrangement of the fifteen symbols. In a case where the CPU  106  determines that at least the predetermined number (five) of the identical symbols is to be rearranged, the CPU  106  activates an award flag indicating an upcoming award so as to provide an award corresponding to the identical symbols described above. The CPU  106  stores the award flag in a predetermined memory area of the RAM  110 . On the other hand, in a case where the CPU  106  does not determine that at least the predetermined number (five) of the identical symbols is to be rearranged (a loosing case) among fifteen symbols, the CPU  106  does not activate the award flag. 
     As a result of the determination of the symbols to be rearranged in Step S 5 , the CPU  106  determines whether a combination of symbols for triggering a switch to a free game has occurred along active lines L 1  to L 5  such as shown in  FIG. 3 , within the symbol display regions  301  to  315 . In a case where the CPU  106  determines a switch to a free game, the CPU  106  activates a free game flag indicating a switch to a free game. The CPU  106  stores the free game flag to a predetermined memory area of the RAM  110 . On the other hand, in a case where the CPU  106  does not determine a switch to a free game, the CPU  106  does not activate the free game flag. Subsequently, the CPU  106  advances the processing to Step S 6 . 
     In Step S 6 , the CPU  106  transmits a signal for starting a dynamical display of symbols in each of the symbol display regions  301  to  315  corresponding to the fifteen video reels respectively, to the display/input controller  140 . Upon the start of a dynamical display of a set of symbols performed by each of the fifteen video reels, the CPU  106  stands by for a predetermined period of time to elapse (Step S 7 ). When the predetermined period of time has elapsed (“YES” in Step S 7 ), the CPU  106  transmits a signal for executing the rearrangement of a symbol of each of the fifteen video reels which correspond to the symbol display regions  301  to  315  respectively, to display/input controller  140 . As a result, the symbols of the fifteen video reels are rearranged (Step S 8 ). Subsequently, the CPU  106  advances the processing to Step S 9 . 
     In Step S 9 , the CPU  106  determines whether the award flag stored in the RAM  110  is activated in Step S 5  in the processing for determining symbols to be rearranged. In a case where the award flag is not activated (“NO” in Step S 9 ), the CPU  106  terminates the routine. On the other hand, in a case where the award flag is activated (“YES” in Step S 9 ), the CPU  106  advances the processing to Step S 10 . 
     In Step S 10 , the CPU  106  determines whether the free game stored in the RAM  110  is activated in Step S 5  in the processing determining symbols to be rearranged. More specifically, in a case where the free game flag is activated (“YES” in Step S 10 ), the CPU  106  advances the processing to Step S 11 . On the other hand, in a case where the free game flag is not activated (“NO” in Step S 10 ), the CPU  106  advances the processing to S 12 . 
     In Step S 11 , the CPU  106  executes free game processing. More specifically, the CPU  106  starts a free game and performs free games a predetermined times. Subsequently, the CPU  106  terminates the routine. 
     In Step S 12 , the CPU  106  pays out coins corresponding to the number of rearranged identical symbols of at least the predetermined number (five). Here, in a case where there is a wild symbol, which is substitutable for any kind of symbol, the number of wild symbols may be included in the number of the identical symbols. More specifically, the CPU  106  refers to a payout table (not shown) and calculates a payout amount of coins corresponding to the number of rearranged identical symbols of at least the predetermined number (five). The CPU  106  reads the credit amount stored in the RAM  110 , adds the calculated payout amount to the credit amount thus read, and stores the resulting value in a predetermined memory area of the RAM  110 . The CPU  106  causes the credit amount display unit  49  to display the stored credit amount. Subsequently, the CPU  106  terminates the routine. 
       FIG. 7  is a flow chart showing an example of the free game processing (S 11 ) in  FIG. 6 .  FIG. 9  is a diagram showing a payout table related to a free game.  FIGS. 10 and 11  are examples of display screens of rendered images of a game, each displayed by the gaming machine  10  according to the present invention. A description is provided referring to those figures arbitrarily. 
     In Step S 1101 , the CPU  106  determines a specific symbol associated with a free game. For example, the CPU  106  determines symbols arranged along an active line that have triggered a switching to a free game in a basic game as a specific symbol. More specifically, as shown in  FIG. 10 , a basic game is performed with the symbol display regions  301  to  315  on the liquid crystal display  30  as the symbol display area for providing an award, and in a case where a combination of symbols (“BIG WAVE” symbols) (the combination including the symbol display regions  301 ,  305 ,  309 ,  311  and  313 ) is achieved along the active line L 4  (refer to  FIG. 3 ), the CPU  106  determines a “BIG WAVE” symbol, which has triggered a switch to a free game, as a specific symbol. 
     A way to determine a specific symbol is not limited thereto, and an arrangement may be made in which a player can select a specific symbol. For example, a touch panel mechanism for a display may be utilized (refer to numeral  32  in  FIG. 5 ). In other words, upon selecting one of the symbol display regions  301  to  315  in the symbol display area for providing an award via the touch panel  32 , the CPU  106  recognizes the selection, and determines a symbol in the selected symbol display region as a specific symbol. 
     A display to allow a player to select a specific symbol may include: the display screen, which has triggered a switch to a free game such as the abovementioned display screen shown in  FIG. 10 , and a new display screen, as an initial screen of a free game (for example, a screen displaying a rendered image showing symbols repeatedly rearranged in slow motion, in which all the symbols used in the free game can be observed). 
     Data related to the specific symbol determined in Step S 1101  is stored in the RAM  110  and is utilized in processing for determining symbols (S 1103 ) and processing for extracting pattern data to be rearranged (S 1104 ), which are described later. In addition, a higher probability is applied to the specific symbol to be rearranged in one of the symbol display regions  301  to  315 . Subsequent to the processing of Step S 1101 , the CPU  106  advances the processing to the Step S 1102 . 
     In Step S 1102 , the CPU  106  transmits a signal for starting a dynamical display of a set of symbols in each of the symbol display regions  301  to  315  to the display/input controller  140 , causing each of the fifteen video reels to display a dynamical display. Subsequently, the CPU  106  advances the processing to Step S 1103 . 
     In Step S 1103 , the CPU  106  determines whether to display at least a predetermined number (for example, three) of specific symbols, a kind of symbols to be rearranged in a group of the same kind, and isolated symbols to be rearranged. Subsequently, the CPU  106  advances the processing to Step S 1104 . 
     In Step S 1104 , the CPU  106  refers to a rearrangement pattern table (not shown), and extracts rearrangement pattern data corresponding to the symbols to be rearranged, which are determined in the processing of Step S 1103 . Furthermore, the CPU  106  stores the data thus extracted to a predetermined memory area of the RAM  110 . Subsequently, the CPU  106  advances the processing to Step S 1105 , and in Step S 1105 , the CPU  106  rearranges symbols based on the extracted rearrangement pattern data. For example, as shown in  FIG. 11 , the CPU  106  rearranges the predetermined symbol in each of the symbol display regions  301  to  315  based on the rearrangement pattern data. Subsequently, the CPU  106  advances the processing to Step S 1106 . 
     In Step S 1106 , the CPU  106  determines whether at least the predetermined number of specific symbols is rearranged among the rearranged symbols. In the present embodiment, the predetermined number is three. For example, referring to  FIG. 11 , “BIG WAVE” symbols, which are the specific symbols, are rearranged in the symbol display regions  307 ,  308 ,  311 , and  313 . This indicates that the number of specific symbols satisfies the requirement of rearrangement, or the minimum predetermined number (three). The symbol display regions  307 ,  308 ,  311  and  313  may be displayed with visual effects, which allow a player to easily comprehend the game. For example, the symbol display regions  307 ,  308 ,  311  and  313  may be highlighted by lights. 
     Suppose a case of a game in which a player can select a specific symbol. If the player selects an “ANEMONE FISH” symbol as a specific symbol, the rearrangement requirement of at least the predetermined number (three) of the specific symbols is satisfied since “ANEMONE FISH” symbols are rearranged in the symbol display regions  309 ,  302 , and  315 . Furthermore, in a case where a “TURTLE” symbol has been selected as a specific symbol, the rearrangement requirement of at least the predetermined number (three) of the specific symbols is satisfied since “TURTLE” symbols are determined as having been rearranged in the symbol display regions  301 ,  303 , and  304 , by including a “WILD” symbol. 
     In the Step S 1106 , in a case where the CPU  106  determines that at least the predetermined number of the specific symbols are rearranged, the CPU  106  increments a count value X (Step S 1107 ). Subsequently, the CPU  106  advances the processing to Step S 1109 . 
     On the other hand, in a case where the CPU  106  determines that at least the predetermined number of the specific symbols are not rearranged in Step S 1106 , the count value X is reset to “0” (Step S 1108 ). The count value X is stored in the RAM  110 . Subsequently, the CPU  106  advances the processing to Step S 1110 . 
     In Step S 1109 , the CPU  106  provides an award corresponding to the count value X. Providing an award based on the count value X is a type of processing to increase a payout amount of a predetermined award based on the number of consecutive rounds in each of which the specific symbol is rearranged, while performing a free game. 
     For example, an award qualified in a basic game that has been performed before a switch to a free game is carried over at the start of a free game. The award is set as a base award. The base award may be set so as to vary depending on a combination of symbols and the kind of symbols forming a combination. A credit amount applied to the base award is stored in a predetermined memory area of the RAM  110 , for example. The CPU  106  increases a payout amount for the base award by addition or multiplication of a value, which is determined based on the number of consecutive rounds of the free game in each of which the specific symbol is rearranged. 
     More specifically, the award is provided referring to a payout table for a free game shown in  FIG. 9 . For example, for a free game having five games, the award increases as the number of consecutive games (X) equivalent with the count value X described above increases. For example, the award increases with respect to a base award of a predetermined value A according to the number of consecutive games (X) in the following manner: B equals 2A, C equals A×B, and D equals A×B×C. The selection of values A, B, C and D is not limited to the example described above, but there may be several alternatives. Referring to the payout table mentioned above, the CPU  106  reads a credit amount of the base award stored in the RAM  110 , and multiplies (or adds) the credit amount thus read by a calculated (recalculated) payout amount, for example. Subsequently, the CPU  106  stores the resulting value to a predetermined memory area of the RAM  110 . The CPU  106  displays the stored value on the credit amount display unit  49 . Subsequent to the processing of Step S 1109 , the CPU  106  advances the processing to Step S 1110 . 
     In Step S 1110 , the CPU  106  increments the number of games N. The number of games N is stored in the RAM  110 . In the following Step S 1111 , the CPU  106  determines whether the number of games N is equal to or greater than a predetermined value. The predetermined value in the present embodiment is five. In other words, in the present embodiment, when a game is advanced to a free game from a basic game, symbols are rearranged five times. That is, the CPU  106  advances the processing to Step S 1102  in a case where the CPU  106  determines that the number of games N is less than a predetermined value (N=5), and advances the processing to Step S 1120  in a case where the CPU  106  determines that the number of games N equals the predetermined value (N=5). In Step S 1120 , the CPU  106  resets the count value X and the number of games N, and terminates the routine. 
     According to the abovementioned embodiment of the present invention, a free game including the processing in Step S 1102  to S 1110  is performed, until the number of games N reaches a predetermined value (for example, N=5). During the free game, each time specific symbols are rearranged in the symbol display area for providing an award (the symbol display regions  301  to  315  in the present embodiment), an award is displayed on the display  30 , which equals the base award multiplied by (or added to) the value determined according to the number of consecutive rounds of the free game in each of which the specific symbol is rearranged. With such a configuration, the gaming machine can provide a player-friendly game with speed and excitement without interruption of a game flow. 
       FIG. 8  is a flow chart showing another example of free game processing (S 11 ) in  FIG. 6 . Since the processing of Step S 1101  to S 1106  is the same as that of  FIG. 7 , a description for the same portion is omitted. 
     In a case where the CPU  106  determines that at least a predetermined number (three) of specific symbols is rearranged in the processing of Step S 1106 , the CPU  106  increments the count value X (Step S 1107 ). Subsequently, the CPU  106  advances the processing to S 1110 . 
     On the other hand, in a case where the CPU  106  determines that the specific symbols less than a predetermined number are rearranged, the CPU  106  advances the processing to Step S 1109   a . In Step S 1109 , the CPU  106  provides an award based on a count value X. Providing the award based on the count value X is a type of processing to increase a payout amount of a base award based on the number of consecutive rounds in each of which the specific symbol is rearranged while performing a free game (refer to explanation of  FIG. 7 , as an example). In other words, in a case where the specific symbols are not rearranged in the symbol display area for providing an award, the CPU  106  pays out an award corresponding to the number of consecutive games (X) that has been stored for the specific symbol rearranged in a previous game. More specifically, an award is provided referring to a payout table for a free game shown in  FIG. 9 . Furthermore, similar to the description of  FIG. 7 , the CPU  106  determines a base award according to a display pattern of symbols in the symbol display area for providing an award that has triggered a switch from a basic game to a free game. The CPU  106  provides an increased award based on the base award according to the number of consecutive games (X) of the rearranged specific symbol, which has been stored for the previous game. Subsequently, the CPU  106  resets the count value X to 0 (Step S 1108 ). The CPU  106  advances the processing to S 1110 . 
     In Step S 1110 , the CPU  106  increments the number of games N. The number of games N is stored in the RAM  110 . In the following Step S 1111 , the CPU  106  determines whether the number of games N is equal to or greater than a predetermined value. 
     In a case where the CPU  106  determines that the number of games N is less than the predetermined value (N=5), the CPU  106  advances the processing to Step S 1102 . In other words, after executing the processing of providing an award based on the number of consecutive games (X) for the game in which the specific symbol is rearranged prior to the current game in which a consecutive rearrangement of the specific symbol is stopped, the CPU  106  resets the number of consecutive games (X) and performs subsequent games. 
     In a case where the CPU  106  determines that the number of games N reaches the predetermined value (N=5), the CPU  106  advances the processing to Step S 1112 . In Step S 1112 , the CPU  106  compares the count value X and the number of games N, and in a case where the CPU  106  determines that they are the same value, the CPU  106  advances the processing to Step S 1109   b . In other words, in a case where the specific symbol is rearranged in each round of a free game and the CPU  106  determines that the number of consecutive games (X) is equal to the number of games N, there is no step to provide an award until the number of games N equals the predetermined number of free games. Thus, undergoing Step  1109   b  which is similar to the Step S 1109   a , the CPU  106  provides an award, which is an increased award with respect to the base award (based on the count value X). Subsequently, the CPU  106  advances the processing to Step S 1120 , resets the count value X and the number of games N, and terminates the routine. 
     According to the abovementioned embodiment of the present invention, a free game including the processing in Step S 1102  to S 1110  is performed, until the number of games N reaches a predetermined value (for example, N=5). During the free game, each time the specific symbol is rearranged in the symbol display area for providing an award (the symbol display regions  301  to  315  in the present embodiment), the gaming machine grades up a factor to be multiplied (or added) to the base award displayed on the display  30 . In a case where the specific symbol is not rearranged in the symbol display regions  301  to  315  in a subsequent game, the gaming machine provides the factor graded up in the previous game so as to multiply it to the base award. With such a configuration, the gaming machine can provide a player-friendly game with speed and excitement without interruption of a game flow. 
     While the embodiment of the gaming machine according to the present invention has been described, it is to be understood that the above description is intended to be illustrative, and not restrictive, and any changes in design may be made to specific configurations such as various means. Moreover, it should be understood that the advantages described in association with the embodiments are merely a listing of most preferred advantages, and that the advantages of the present invention are by no means restricted to those described in connection with the embodiments. 
     For example, although a description is provided of the present invention that an award is provided when a group of symbols forms a combination of symbols along an active line during a free game (bonus game), an award may alternatively be provided when a combination of symbols based on the number of identical symbols occurs. 
     Furthermore, although the description is provided that the base award is used in a free game, when a game is advanced to a free game from a basic game, the base award may be omitted, and the award may be increased based on the number of consecutive rounds in each of which a specific symbol is rearranged during a free game, for example. 
     Moreover, in the present embodiment, the symbol display regions  301  to  315  on the liquid crystal display  30  of the gaming machine  10  are a matrix of three rows and five columns in which the video reels are provided, respectively, but it is not limited thereto. Alternatively, a video reel or a mechanical reel that is divided into five columns may be adopted. In this case, the symbol display regions  301  to  303  are included in the first column which is divided into a plurality of symbol display regions, the symbol display regions  304  to  306  are included in the second column which is divided into a plurality of symbol display regions, the symbol display regions  307  to  309  are included in the third column which is divided into a plurality of symbol display regions, the symbol display regions  310  to  312  are included in the fourth column which is divided into a plurality of symbol display regions, and the symbol display regions  313  to  315  are included in the fifth column which is divided into a plurality of symbol display regions.