Patent Publication Number: US-2015087387-A1

Title: Gaming Machine

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims a priority from the prior Japanese Patent Application No. 2013-194982 filed on Sep. 20, 2013, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a gaming machine. 
     2. Background of the Related Art 
     Conventionally, there has been known a gaming machine in which when subsequent to the insertion of gaming media such as coins, a player presses a spin button, symbols to be displayed for the player upon stopping a plurality of reels are determined by lottery processing; scrolling of symbol arrays of the reels is started; the scrolling is stopped so as to display the determined symbols for the player and to rearrange the symbols; it is determined whether or not a combination of the displayed symbols is associated with a prize; and in a case where the combination of the displayed symbols is associated with the prize, a bonus according to a kind of the winning combination of the symbols is awarded to the player. 
     In such a gaming machine, upon winning a BB related to the activation of a bonus, a number of gaming media which can be paid out in a bonus game is determined and set (for example, refer to Japanese Unexamined Patent Application Publication No. 2007-20954). On this gaming machine, a player can play the bonus game until the set number of gaming media has been reached. 
     However, in such a gaming machine, after winning the BB related to the activation of the bonus, the game is merely played until the medals whose allowable number is determined have been paid out. Therefore, the player merely consumes the predetermined allowable number of medals and thus, game patterns are likely to be monotonous in the bonus game. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a gaming machine capable of realizing game patterns which are different from one another by continuing a bonus game when a predetermined number or more of predetermined symbols are rearranged in the bonus game. 
     A first aspect of the present invention is directed to a gaming machine which includes a symbol display window for displaying a plurality of symbols in display regions of the symbol display window, the gaming machine causing free games to be triggered based on an outcome rearranged in said symbol display window, the gaming machine comprising: 
     a memory for storing a symbol determination table having probabilities set therein, with each of which the plurality of symbols are rearranged in the display regions; and a controller for executing control to rearrange the plurality of symbols in the display regions based on the symbol determination table stored in the memory, the controller being programmed to execute processing (1-1) to (1-3) described below: 
     processing (1-1) in which symbols to be rearranged are randomly determined from the plurality of symbols based on the symbol determination table; 
     processing (1-2) in which when a predetermined number or more of predetermined symbols among the plurality of symbols are rearranged in the display regions as an outcome of the processing (1-1), the free games are continued; and 
     processing (1-3) in which when the predetermined symbols whose number is less than the predetermined number are rearranged in the display regions, the free games are terminated. 
     By employing the above-described configuration of the present invention, when the predetermined number or more of the predetermined symbols are rearranged, the free games are continued, and when the predetermined number or more of the predetermined symbols are not rearranged, the free games are terminated. Accordingly, the number of free games to be continued is varied in accordance with an outcome of the lottery. Thus, since a player does not know the timing at which the free games are terminated, a player can play the games while wishing that the free games are continued. 
     A second aspect of the present invention is directed to a gaming machine which includes a symbol display window for displaying a plurality of symbols in display regions of the symbol display window, the gaming machine causing free games to be triggered based on an outcome rearranged in said symbol display window, the gaming machine comprising: 
     a memory for storing a symbol determination table having probabilities set therein, with each of which the plurality of symbols are rearranged in the display regions in the free games; and 
     a controller for executing control to rearrange in the display regions the plurality of symbols including predetermined symbols for terminating the free games based on the symbol determination table stored in the memory, the controller being programmed to execute processing (2-1) to (2-2) described below: 
     processing (2-1) in which in the free games, symbols to be rearranged are randomly determined from the plurality of symbols based on the symbol determination table; and 
     processing (2-2) in which when the predetermined symbols are displayed in the display regions as an outcome of the processing (2-1) and a termination condition is established, the free games are terminated. 
     By employing the above-described configuration of the present invention, when the predetermined symbols are rearranged, the free games are terminated. Accordingly, the number of free games to be continued is varied in accordance with an outcome of the lottery. Thus, since a player does not know the timing at which the free games are terminated, a player can play the games while wishing that the free games are continued. 
     A third aspect of the present invention is directed to the gaming machine in the second aspect in which when the predetermined symbols are not displayed in the display regions as an outcome of the processing (2-1), the controller executes processing (2-3) in which the free games are continued. 
     By employing the above-described configuration of the present invention, a player can play the games while wishing that the predetermined symbols are not rearranged. 
     It is more preferable that in a case where the display regions are constituted of a plurality of reels and the order of stopping the plurality of reels is defined, the predetermined symbols for terminating the free games are previously set such that the predetermined symbols appear on the reels which lastly stop, instead of the reels which first stop and the predetermined symbols do not appear on the reels which first stop. This is because the present invention gives consideration to the below-described situation. If the predetermined symbols appear on the reels which first stop, a player realizes in the stage where a unit game has not yet been terminated that the free games are not continued, thereby leading to a reduction in amusement. 
     By employing the above-described configuration of the present invention, in the free games, a probability with which a certain combination is established can be changed for each game. 
     A gaming machine capable of realizing game patterns differing from one another in a bonus game is provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a chart showing an outline of a gaming machine; 
         FIG. 2  is a diagram showing a functional flow of operation in the gaming machine; 
         FIG. 3  is a view showing a game system including gaming machines; 
         FIG. 4  is a view showing an entire construction of each of the gaming machines; 
         FIG. 5  is a schematic diagram illustrating a layout of buttons of a control panel of the gaming machine; 
         FIG. 6  is an electric block diagram of the gaming machine; 
         FIG. 7  is a block diagram showing an electric circuit of a reel assembly; 
         FIG. 8  a block diagram showing processing of game programs executed by a main CPU of a motherboard; 
         FIG. 9  shows an example of a payline definition table defining paylines; 
         FIG. 10  shows an example of a symbol determination table for a basic game; 
         FIG. 11  shows an example of a payout table; 
         FIG. 12  is a diagram showing a pattern of state transition in the gaming machine; 
         FIG. 13  is a flowchart of main control processing in the gaming machine; 
         FIG. 14  is a flowchart of coin entry/start check processing in the gaming machine; 
         FIG. 15  is a flowchart of symbol lottery processing for the basic game in the gaming machine; 
         FIG. 16  is a flowchart of symbol display control processing in the gaming machine; 
         FIG. 17  is a flowchart of number-of-payout determination processing in the gaming machine; 
         FIG. 18  is a flowchart of feature game processing in the gaming machine; 
         FIG. 19  is a flowchart of symbol lottery processing for free games in the gaming machine; 
         FIGS. 20A and 20B  show an example of a symbol determination table first and second selection table; 
         FIG. 21  shows an example of a first symbol determination table for the free games; 
         FIG. 22  shows an example of a second symbol determination table for the free games; 
         FIG. 23  shows an example of a third symbol determination table for the free games; 
         FIG. 24  shows an example of a fourth symbol determination table for the free games; 
         FIG. 25  shows an example of a fifth symbol determination table for the free games; 
         FIG. 26  shows an example of a sixth symbol determination table for the free games; 
         FIG. 27  shows an example of a seventh symbol determination table for the free games; 
         FIG. 28  shows an example of an eighth symbol determination table for the free games; 
         FIG. 29  shows an example of a ninth symbol determination table for the free games; 
         FIG. 30  shows an example of a tenth symbol determination table for the free games; 
         FIG. 31  shows an example of a symbol determination table for a basic game; 
         FIG. 32  shows an example of a payout table; 
         FIG. 33  is a diagram showing a pattern of state transition in a gaming machine; 
         FIG. 34  is a flowchart of feature game processing in the gaming machine; 
         FIG. 35  is a flowchart of symbol lottery processing for free games in the gaming machine; 
         FIGS. 36A and 36B  show an example of a symbol determination table first and second selection table; 
         FIG. 37  shows an example of a first symbol determination table for the free games; 
         FIG. 38  shows an example of a second symbol determination table for the free games; 
         FIG. 39  shows an example of a third symbol determination table for the free games; 
         FIG. 40  shows an example of a fourth symbol determination table for the free games; 
         FIG. 41  shows an example of a fifth symbol determination table for the free games; 
         FIG. 42  shows an example of a sixth symbol determination table for the free games; 
         FIG. 43  shows an example of a seventh symbol determination table for the free games; 
         FIG. 44  shows an example of an eighth symbol determination table for the free games; 
         FIG. 45  shows an example of a ninth symbol determination table for the free games; 
         FIG. 46  shows an example of a symbol determination table for a basic game; 
         FIG. 47  shows an example of a payout table; 
         FIG. 48  is a diagram showing a pattern of state transition in a gaming machine; 
         FIG. 49  is a flowchart of feature game processing in the gaming machine; 
         FIG. 50  is a flowchart of symbol lottery processing for the free games in the gaming machine; 
         FIG. 51  shows an example of a symbol determination table selection table; 
         FIG. 52  shows an example of a first symbol determination table for free games; 
         FIG. 53  shows an example of a second symbol determination table for the free games; 
         FIGS. 54A to 54C  are diagrams illustrating an example of effects; and 
         FIGS. 55A to 55C  are diagrams illustrating an example of effects. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments will be described with reference to the accompanying drawings. 
     &lt;&lt;&lt;Outline of Gaming Machine According to Embodiments&gt;&gt;&gt; 
       FIG. 1  is a chart showing an outline of a gaming machine according to each of the embodiments of the present invention. 
     The gaming machine according to each of the embodiments of the present invention determines symbols to be rearranged in a basic game by conducting a lottery (step S 1 ). When the symbols rearranged in the basic game meet a predetermined condition (for example, a condition that a combination of the symbols rearranged on a payline is a combination of BELL symbols or SEVEN symbols), the gaming machine shifts the game to free games (step S 2 ). Upon shifting to the free games, said gaming machine determines symbols to be rearranged by conducting a lottery based on a symbol determination table (step S 3 ). When a predetermined number (for example, three) or more of predetermined symbols (for example, BELL symbols) are rearranged, the free games are continued, and when the predetermined number (for example, three) or more of the predetermined symbols (for example, the BELL symbols) are not rearranged, the free games are terminated and the game is reverted to the basic game (step S 4 ). Said gaming machine repeatedly executes these steps S 1  to S 4 . 
     [Description of Functional Flowchart] 
     With reference to  FIG. 2 , basic functions of the gaming machine according to each of the embodiments will be described.  FIG. 2  is a diagram showing a functional flow of operation in the gaming machine according to each of the embodiments of the present invention. 
     &lt;Coin Entry/Start Check&gt; 
     First, the gaming machine checks whether or not any BET button has been pressed by a player and subsequently, checks whether or not a spin button has been pressed by a player. 
     &lt;Determination of Symbols&gt; 
     Next, when the spin button has been pressed by the player, the gaming machine extracts random number values for determination of symbols and determines symbols to be displayed for the player when scrolling of symbol arrays has been stopped, so as to correspond to each of a plurality of reels that are displayed on the display. 
     &lt;Determination of Winning&gt; 
     Next, the gaming machine determines whether or not a combination of the symbols displayed for the player is associated with any winning. 
     &lt;Display of Symbols&gt; 
     Next, the gaming machine starts scrolling of symbol arrays of each of the reels, stops the scrolling so as to rearrange symbols such that the determined symbols are displayed for the player. 
     &lt;Payout&gt; 
     Next, when a combination of the symbols displayed for the player is associated with any winning, the gaming machine awards a bonus to the player according to a kind of the combination of the symbols. For example, the gaming machine pays out to the player coins in number according to the combination of the symbols when a combination of symbols associated with paying-out of coins is displayed. 
     &lt;Free Games&gt; 
     In addition, in the gaming machine according to each of the embodiments, when a combination of symbols associated with a feature game trigger is displayed, the gaming machine shifts the game to the free games. It is to be noted that each of the free games is a game in which each lottery relevant to the above-mentioned determination of symbols is conducted over a predetermined number of times without consuming any coins. In the free games, the gaming machine extracts random number values for the determination of symbols and determines symbols to be rearranged. When the predetermined number or more of the predetermined symbols are rearranged, the gaming machine continues the free games, and when the predetermined number or more of the predetermined symbols are not rearranged, the gaming machine terminates the free games. 
     In addition, the gaming machine can pay out coins of the amount of a jackpot to the player in a case where the player has won a predetermined level in a jackpot game. The jackpot refers to a function of accumulating a part of coins which are consumed by the player in the gaming machine as the amount of a jackpot and in a case where the player has won the predetermined level of a jackpot, paying out the number of payout according to the amount of a payout of that level. The gaming machine computes the amount which is accumulated as the amount of a jackpot (accumulated amount) each time one game is played and accumulates the amounts as the amount of a jackpot. 
     The jackpot may be of a standalone type such that a single gaming machine is employed and a part of coins consumed in the single gaming machine is accumulated as the amount of jackpot in that gaming machine, or alternatively, may be of a network type such that a jackpot is shared by connecting gaming machines to each other in a single gaming facility or in a plurality of gaming facilities, and the accumulated amount of jackpot is transmitted via an external control device. 
     In the network type, a part of coins consumed by a player in each gaming machine is transmitted as the amount of a jackpot to the external control device, and in the external control device, the received amount of a jackpot is accumulated and is shared by each gaming machine. In a case where a gaming machine has won the predetermined level of a jackpot, the amount of a jackpot is transmitted from the external control device to that gaming machine. 
     In addition, in the gaming machine, in addition to the bonus mentioned above, a bonus such as a mystery bonus may be provided. The mystery bonus is a bonus in which a predetermined amount of coins are paid out by winning in a dedicated lottery. When the spin button is pressed, the gaming machine extracts random number values for the mystery bonus and determines whether or not a mystery bonus trigger is established by conducting the lottery. 
     &lt;&lt;&lt;Embodiments of Gaming Machine&gt;&gt;&gt; 
     Hereinafter, in each of the embodiments of the present invention, as the gaming machine according to each of the embodiments of the present invention, a slot machine  10  will be described. 
     First Embodiment 
     Hereinafter, a First Embodiment of the Present Invention Will be Described. 
     &lt;&lt;Game System&gt;&gt; 
       FIG. 3  is a view showing a game system including slot machines  10  in the first embodiment. 
     The game system  12  includes a plurality of slot machines  10  and an external control device  14 , which are connected via a communication line  16 . 
     The external control device  14  controls the plurality of slot machines  10 . In the embodiment, the external control device  14  is the so-called “hall server” which is installed in a gaming facility having the plurality of slot machines  10 . A unique identification number is assigned to each of the slot machines  10 , and by using the identification numbers, the external control device  14  identifies a source of data which is transmitted from each of the slot machines  10 . In addition, also when data is transmitted from the external control device  14  to each of the slot machines  1 , each of the identification numbers is used to designate a destination. 
     The game system  12  may be constructed in one gaming facility such as a casino in which a variety of games can be played or alternatively, may be constructed among a plurality of gaming facilities. In addition, in a case where the game system is constructed in one gaming facility, the game system  12  may be constructed in each floor or section of the gaming facility. The communication line  16  may be wired or wireless, and a leased line or a switchboard line or the like can be used. 
     &lt;&lt;Construction of Slot Machine  10 &gt;&gt; 
       FIG. 4  is a view showing an entire construction of the slot machine  10  according to the first embodiment of the present invention. 
     As gaming media which can be used in the slot machine  10 , coins, bills, or pieces of electronic information corresponding thereto are included. In addition, credits stored in a bar code ticket or an IC card can be also used as the gaming media used in the slot machine  10 . The gaming media are not limited to the above-mentioned gaming media, and other kinds of media are also used in the same manner. 
     The slot machine  10  shown in  FIG. 4  includes: a cabinet  20 ; a top box  30  installed in the cabinet  20 ; and a main door  22  provided on a front face of the cabinet  20 . 
     A symbol display unit  40  including a reel assembly  50  is provided at the main door  22 . In the present embodiment, the reel assembly  50  includes five reels  52 A,  52 B,  52 C,  52 D, and  52 E. Each of the reels  52 A,  52 B,  52 C,  52 D, and  52 E has a drum whose outer circumferential face has a plurality of kinds of symbols arranged thereon. The symbol display unit  40  is installed on a front part of the reel assembly  50  and has a display window  56 . A reel cover  54  is provided outside so as to allow a player to visually recognize a part of each of the reels  52 A,  52 B,  52 C,  52 D, and  52 E. The reel cover  54  is provided on a display panel  58 . It is preferable that as the reel cover  54 , a transparent liquid crystal panel is used. The symbol display unit  40  includes a touch panel  59  which detects a touch input made by a player. 
     In a state in which the reels  52 A,  52 B,  52 C,  52 D, and  52 E have stopped, three symbols among symbols assigned on each of the reels  52 A,  52 B,  52 C,  52 D, and  52 E appear in the display window  56 . Thus, a symbol matrix constituted of three rows and five columns is formed in the display window  56 . One or more lines are previously set as paylines for determining whether or not winning occurs. Each time a unit game is executed, the reels  52 A,  52 B,  52 C,  52 D, and  52 E to which symbols are assigned rotate at a predetermined speed, thereafter stop, and cause symbols to appear in the display window  56 , thereby rearranging the symbols. An outcome of the unit game is determined by the rearrangement of the symbols. A profit in accordance with an outcome of the unit game is awarded to a player. For example, when a predetermined winning combination is established along one payline by the rearranged symbols, a predetermined amount of a payout is awarded to a player. In addition, a game mode of the subsequent unit game is determined by the rearrangement of the symbols. As the game modes, there are a basic game mode and a free game mode, and the game modes will be described later in detail. 
     In the specification, the unit game refers to a game in a period from when processing of starting credits for starting a game is executed to when the symbol arrays have stopped, any symbols are rearranged in the display window  56 , and termination processing such as paying-out processing in accordance with an outcome of the game is executed. In a case of the free games, since it is not required for a player to perform a bet operation, the time at which credit processing inside of the slot machine  10  is conducted can be made as the time at which a game is started. In addition, in a case of a game other than the free games, the time at which a player performs the bet operation can be made as the time at which the game is started. In addition, processing in accordance with a outcome of a game, which is determined by rearranged symbols, can be made as the termination processing. For example, the time at which winning has occurred and processing of paying-out in accordance with the winning is executed can be made as the time at which the game is terminated. 
     In predetermined regions of the display panel  58 , an amount of bets and an amount of credits are displayed. The amount of credits indicates the number of coins which a player owns and has deposited inside of the slot machine  10 . The amount of payout indicates the number of coins awarded to a player when a winning combination is established. 
     In the first embodiment, in the slot machine  10 , mechanical reels  52 A,  52 B,  52 C,  52 D, and  52 E are used. Video reels or a combination of the mechanical reels and the video reels may be used. 
     An IC card reader  60  is provided in a lower part of the symbol display unit  40 . The IC card reader  60  receives an IC card. In the IC card, identification information of a player and predetermined data such as game log data pertinent to games played by a player before are stored. In addition, in the IC card, data corresponding to coins, bills, or credits owned by a player can also be stored. The IC card reader  60  performs reading and writing from and to an inserted IC card. It is preferable that the IC card reader  60  includes a liquid crystal display for displaying data read from an IC card. 
     In addition, as shown in  FIG. 4  and  FIG. 5 , below the reel assembly  50 , a variety of buttons disposed on a control panel  70  (input device), a coin entry  80  for receiving coins into the cabinet  20 , and a bill entry  82  are provided. 
     On the control panel  70 , a CHANGE button  71 , a CASHOUT/TAKE WIN button  72 , and a HELP button  73  are disposed in an upper part of a left region thereof, and a 1-BET button  74 , a 2-BET button  75 , a 3-BET button  76 , a 4-BET button  77 , a 5-BET button  78 , a play-2-LINE button  90 , a play-10-LINE button  91 , a play-20-LINE button  92 , a play-30-LINE button  93 , and a GAMBLE button  94  are disposed in a lower part of the left region thereof. In addition, the coin entry  80  and the bill entry  82  for receiving bills or the like are disposed in an upper part of a right region thereof and a MAX-BET button  85  and a spin button  86  are disposed in a lower part of the right region thereof. 
     The CHANGE button  71  is an operation button used upon temporarily leaving a seat and making a request of a staff in a gaming facility for exchange of money. The CASHOUT/TAKE WIN button  72  is an operation button used upon adjusting coins (credits) deposited inside of the slot machine  10 . The HELP button  73  is a button to be pressed in a case where a way of operating a game and the like are unclear. When the HELP button  73  is pressed, a variety of pieces of help information are displayed on a video display unit  110  and the reel assembly  50 . 
     Each time the 1-BET button  74  is pressed, one of credits currently owned by a player is bet on each activated payline on a one-by-one basis. The 2-BET button  75  is a button for starting a game with two bets on each activated payline. In addition, the 3-BET button  76  is a button for starting a game with three bets on each activated payline. In addition, the 4-BET button  77  is a button for starting a game with four bets on each activated payline. In addition, the 5-BET button  78  is a button for starting a game with five bets on each activated payline. In addition, the MAX-BET button  85  is a button for starting a game with 10 bets on each activated payline. Accordingly, by pressing any of the 1-BET button  74 , the 2-BET button  75 , the 3-BET button  76 , the 4-BET button  77 , the 5-BET button  78 , and the MAX-BET button  85 , the number of bets placed on each of the activated paylines is determined. 
     The play-2-LINE button  90  activates paylines when pressed, whereby the number of the activated paylines becomes “2”. The play-10-LINE button  91  activates paylines when pressed, whereby the number of the activated paylines becomes “10”. The play-20-LINE button  92  activates paylines when pressed, whereby the number of the activated paylines becomes “20”. The play-30-LINE button  93  activates paylines when pressed, whereby the number of the activated paylines becomes “30”. 
     The GAMBLE button  94  is an operation button used upon shifting to a gamble game after terminating a bonus game or the like. Here, the gamble game is a game played by using obtained credits. 
     The spin button  86  is used upon starting the scrolling of the mechanical reels  52 A,  52 B,  52 C,  52 D, and  52 E. 
     The coin entry  80  is to receive coins into the cabinet  20 . The bill entry  82  is to validate legitimacy of bills and receive legitimate bills into the cabinet  20 . 
     When coins are inserted into the coin entry  80 , the inserted coins are guided to a hopper in the cabinet  20 . When bills are inserted into the bill entry  82 , it is determined whether or not the inserted bills are legitimate and only legitimate bills are received into the cabinet  20 . 
     On a front face of a lower side of the main door  22  and below the control panel  70 , a lower glass  96  and a coin tray  98  are provided. On the lower glass  96 , a character of a slot machine and the like are depicted. To the coin tray  98 , coins are dispensed from the cabinet  20 . 
     As shown in  FIG. 4 , the video display unit  110  having the liquid crystal panel is provided on a front face of the top box  30 . The video display unit  110  is to provide video effects for enhancing amusement of a game. In addition, in the video display unit  110 , information pertinent to rules and operations of a game is also displayed. A speaker  112  and a lamp  114  are provided on a side face and an upper face of the top box  30 , respectively. The slot machine  10  provides sound effects and effects presented by emitting light via the speaker  112  or the lamp  114 , thereby enhancing amusement of a game. 
     Below the video display unit  110 , a ticket printer  120 , a keypad  122 , and a data display  124  are provided. 
     The ticket printer  120  prints on a ticket a bar code including credit data, date and time, and an ID number of the slot machine  10  and discharges the printed ticket as a bar code ticket. A player can exchange the bar code ticket for bills and the like at a predetermined place of a gaming facility (for example, a cashier of a casino). 
     The keypad  122  has a plurality of keys. A player operates the plurality of keys, thereby allowing a variety of instructions related to the issuance of a bar code ticket to be inputted. On the data display  124  having a fluorescent display tube, an LED, and the like, data inputted from the keypad  122  by a player is displayed. 
     &lt;&lt;&lt;Electric Configuration of Slot Machine&gt;&gt;&gt; 
       FIG. 6  is an electric block diagram of the slot machine  10  shown in  FIG. 4 . The slot machine  10  includes a game board  200 , a motherboard  220 , a door PCB  230 , and a main body PCB  240 . 
     The game board  200  includes: a CPU  202 ; a ROM  204  which can be accessed from the CPU  202  via an internal bus; and a boot ROM  206  which can be accessed from the CPU  202  via the internal bus. The game board  200  includes: an IC socket  208  which is capable of housing a memory card  210  and communicating with the memory card  210 ; and a card slot  212  which is provided in correspondence with a general-purpose array logic (GAL)  214 . 
     The memory card  210  includes a nonvolatile memory and has a game program and a game system program stored therein. 
     The IC socket  208  is configured such that the memory card  210  can be removably mounted thereon. The IC socket  208  is connected to the motherboard  220  by an IDE bus. A game executed by the slot machine  10  can be changed by replacing the memory card  210  with another card. In addition, a game executed by the gaming machine  10  can be changed by pulling out the memory card  210  from the IC socket  208 , writing another program into the memory card  210 , and reinserting the memory card  210  into the IC socket  208 . 
     The GAL  214  is a kind of a programmable logic device (PLD) having a fixed OR array architecture and has a plurality of input ports and output ports. Upon receiving predetermined data via each of the input ports, the GAL  214  outputs data corresponding to the inputted data via each of the output ports. 
     The card slot  212  is configured such that the GAL  214  can be inserted into the card slot  212  or can be removed from the card slot  212  and is connected to the motherboard  220  by a PCI bus. 
     The CPU  202 , the ROM  204 , and the boot ROM  206  which are interconnected by an internal bus are connected to the motherboard  220  by the PCI bus. The PCI bus enables transmission of a signal between the motherboard  220  and the game board  200 , and can supply power from the motherboard  220  to the game board  200 . 
     The ROM  204  stores programs. The boot ROM  206  stores a preliminary authentication program and boot codes or the like, which are used by the CPU  202 , for starting up the preliminary authentication program. The authentication program is a tampering check program for authenticating that the game program and the game system program are each authentic. The preliminary authentication program is a program for authenticating that the authentication program is authentic. Each of the authentication program and the preliminary authentication program is written by processing for authenticating that a targeted program is not tampered. 
     As the motherboard  220 , a generally available mainboard is used, and the motherboard  220  executes the game program and the game system program. The motherboard  220  includes a main CPU  222 , a ROM  224 , a RAM  226 , and a communication interface  228 . 
     The ROM  224  is a memory device for storing programs that are executed by the main CPU  222 , and as in a BIOS, the programs are permanently held together with other pieces of data. The ROM  224  may be a flash memory. The BIOS program initializes peripheral devices when the program is executed by the main CPU  222 . In addition, the BIOS program loads the game program and the game system program which are stored in the memory card  210 , via the game board  200 . The ROM  224  may be rewritable. Alternatively, a write-protected storage medium may be used as the ROM  224 . 
     The RAM  226  stores data and programs used during the operation of the main CPU  222 . For example, when the game program, the game system program, or the authentication program is loaded, such a program can be stored in the RAM  226 . The RAM  226  has a workspace for executing the programs. For example, in the workspace, the number of bets, the amount of payout, the amount of credits, or the like is stored and is held while a game is executed. Symbols, symbol codes, winning combinations, and a plurality of tables defining probabilities thereof are also held while a game is executed. Further, the RAM  226  stores a symbol code determination table. The symbol code determination table stores mapping information between the symbol codes and random numbers used to determine symbols based on the random numbers. In particular, the RAM  226  holds a mode flag as well as a game counter. The mode flag is a flag indicating a game mode. The game counter counts a value indicating the number of unit games that have already been executed or the number of remaining unit games. 
     In addition, the RAM  226  stores the count values of a plurality of counters. As the plurality of counters, a bet counter, an amount-of-payout counter, an amount-of-credit counter, and a number-of-free-game counter for counting the number of unit games in the free games are included. In addition, some of the count values may be held in an internal register of the main CPU  222 . 
     The main CPU  222  communicates with an external controller via the communication interface  228 . For example, the external controller may be constituted of a server (not shown) or the like connected via a communication path. 
     The motherboard  220  is connected to the door PCB  230  and the main body PCB  240 . The motherboard  220  can communicate with the door PCB  230  and the main body PCB  240  via a USB. The motherboard  220  is connected to a power source  252 . The main CPU  222  of the motherboard  220  is started up and operated by using the power supplied from the power source  252 . The motherboard  220  supplies a part of the power to the game board  200  via the PCI bus in order to start up the CPU  202 . The door PCB  230  and the main body PCB  240  are connected to input devices. As the input devices, there are switches, sensors, peripheral devices, and the like, and operations thereof are controlled by the main CPU  222 . The door PCB  230  is connected to the control panel  70 , a coin counter  232 , a reverter  234 , and a cold cathode tube  236 . 
     The control panel  70  has a CHANGE switch  71 S, a CASHOUT/TAKE WIN switch  72 S, a HELP switch  73 S, a 1-BET switch  74 S, a 2-BET switch  75 S, a 3-BET switch  76 S, a 4-BET switch  77 S, a 5-BET switch  78 S, a MAX-BET switch  85 S, a spin witch  86 S, a play-2-LINE switch  90 S, a play-10-LINE switch  91 S, a play-20-LINE switch  92 S, a play-30-LINE switch  93 S, and a GAMBLE switch  94 S which are provided in correspondence with a variety of buttons  71  to  78 ,  85 ,  86 , and  90  to  94 , respectively. Each of the switches  71 S to  78 S,  85 S,  86 S, and  90 S to  94 S detects that each of the buttons  71  to  78 ,  85 ,  86 , and  90  to  94  is pressed by a player and outputs a signal to the main CPU  222 . 
     The coin counter  232  and the reverter  234  are provided in a coin entry  80 . The coin counter  232  determines whether or not a coin inserted into the coin entry  80  is authentic, based on features such as a material and a shape of the coin. In a case where an authentic coin is detected, the coin counter  232  outputs a signal to the main CPU  222 . A coin which is not determined to be authentic is ejected to the coin tray  98 . The reverter  234  operates based on a control signal from the main CPU  222 . The reverter  234  supplies the coin which is determined to be authentic by the coin counter  232  to either a hopper  242  or a cashbox (not shown). In a case where the hopper  242  is not filled with coins, such coins are guided to the hopper  242 . On the other hand, in a case where the hopper  242  is filled with coins, such coins are guided to the cashbox. 
     The cold cathode tube  236  is provided on a rear face of the video display unit  110 . The cold cathode tube  236  functions as a backlight or alternatively, performs illumination based on a control signal from the main CPU  222 . 
     The main body PCB  240  is connected to the speaker  112 , the lamp  114 , the hopper  242 , a coin detector  244 , the touch panel  59 , a bill validator  246 , the reel assembly  50 , the IC card reader  60 , a graphic board  250 , the ticket printer  120 , a key switch  122 S, or the data display  124 . 
     The lamp  114  turns ON or OFF based on a control signal from the main CPU  222 . The speaker  112  outputs a sound such as background music (BGM) based on a control signal from the main CPU  222 . 
     The hopper  242  operates based on a control signal from the main CPU  222  and pays out coins, whose amount of payout is specified, to the coin tray  98  via a coin payout exit (not shown) formed between the lower glass  96  and the coin tray  98 . The coin detector  244  detects the coins which are paid out from the hopper  242  and outputs a detection signal to the main CPU  222 . 
     The touch panel  59  detects a position touched by a player and supplies a position detection signal according to the detected position to the main CPU  222 . The bill validator  246  provided in the bill entry  82  supplies a bill detection signal corresponding to the amount of bill to the main CPU  222  when an authentic bill is detected. 
     The graphic board  250  controls the video display unit  110  and the display panel  58  of the symbol display unit  40  in accordance with a control signal from the main CPU  222 . The graphic board  250  includes: a video display processor (VDP) adapted to generate video data; and a video RAM adapted to temporality store video data. The video data is generated from the game program which is stored in the RAM  226 . 
     The IC card reader  60  reads out data which is stored in an IC card inserted into the IC socket  208  and supplies the read-out data to the main CPU  222 . The IC card reader  60  writes data supplied to the main CPU  222  to the IC card. 
     In order to output a barcode ticket, the ticket printer  120  prints, on the ticket, a barcode including the amount of credits stored in the RAM  226 , date and time, and an identification number of the gaming machine  10 , in accordance with a control signal from the main CPU  222 . 
     The key switch  122 S is provided on a back side of the keypad  122  and when the keypad  122  is pressed by a player, a key detection signal is outputted to the main CPU  222 . 
     The data display  124  displays information relevant to information inputted via the keypad  122 , in accordance with a control signal from the main CPU  222 . 
     &lt;&lt;Electric Circuit of Reel Assembly&gt;&gt; 
       FIG. 7  is a block diagram showing an electric circuit of the reel assembly. 
     As shown in  FIG. 7 , the main body PCB  240  is electrically connected to the reel assembly  50 . As mentioned above, the reel assembly  50  includes the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E. Each of the reels  52 A,  52 B,  52 C,  52 D, and  52 E is provided on a reel circuit board  260 . The reel circuit board  260  includes: an input/output (I/O) unit  262  which can communicate with the main body PCB  240 ; a reel driver  264  that is connected to the I/O unit  262 ; a backlight driver  266 ; and an effect illumination driver  268 . 
     The I/O unit  262  is connected to a magnetic field detector  270 . The magnetic field detector  270  includes: a magnetic sensor adapted to detect an intensity of a magnetic field and then output a magnetic detection signal which is proportional to the intensity of the magnetic field; and a sensor fixing part for fixing the magnetic sensor at a predetermined position. The magnetic sensor detects the intensity of the magnetic field which is generated by a magnet. The magnet is provided on a rotary shaft of a reel motor  272 , and rotates together with the reel  52 A. 
     The reel driver  264  supplies power to the reel motor  272 . The backlight driver  266  supplies individually power to respective light sources  282  of the backlight device  280 . The effect illumination driver  268  supplies individually power to respective light sources  292  of an effect illumination device  290 . 
     Each of the second to fifth reels  52 B to  52 E has the same configuration as that of the first reel  52 A and a detailed description thereof will be omitted. 
     &lt;&lt;Processing of Game Program&gt;&gt; 
       FIG. 8  is a block diagram showing processing of the game programs executed by the main CPU  222  of the motherboard  220 . When power is supplied to the slot machine  10 , the main CPU  222  reads the authenticated game program and game system program from the memory card  210  via the game board  200  and writes these programs into the RAM  226 . The game program is executed in a state in which the program is thus loaded into the RAM  226 . 
     According to the preferable embodiment, the game programs are executed by: an input/credit check processing part  300 ; a random number generation processing part  302 ; a symbol determination processing part  304 ; a game counter processing part  306 ; a reel control processing part  308 ; a winning determination processing part  310 ; an effect control processing part  312 ; a payout processing part  314 ; and a game mode determination processing part  316 . 
     It is to be noted that the input/credit check processing part  300  may be a single input/credit check processing device  300 ′; the random number generation processing part  302  may be a single random number generation processing device  302 ′; the symbol determination processing part  304  may be a single symbol determination processing  304 ′; the game counter processing part  306  may be a single game counter processing device  306 ′; the reel control processing part  308  may be a single reel control processing device  308 ′; the winning determination processing part  310  may be a single winning determination processing device  310 ′; the effect control processing part  312  may be a single effect control processing device  312 ′; the payout processing part  314  may be a single payout processing device  314 ′; and the game mode determination processing part  316  may be a single game mode determination processing device  316 ′. As mentioned above, the game programs in the present embodiment can be executed by a set of the single devices. In addition, the game programs in the present embodiment can be executed by a device obtained by integrating some of the above-mentioned single devices. In any case, it is only required for such device or devices to be a module, a device, or a unit capable of executing the game programs in the present embodiment. 
     &lt;Input/Credit Check Processing Part  300 &gt; 
     The input/credit check processing part  300  continuously checks whether either any one of the 1-BET button  74  to 5-BET button  78 , the MAX-BET button  85 , or the spin button  86  is pressed in an idle state in which spinning of the reels  52 A,  52 B,  52 C,  52 D, and  52 E stops. In a case where either any one of the 1-BET button  74  to 5-BET button  78 , the MAX-BET button  85 , or the spin button  86  is pressed, the input/credit check processing part  300  checks whether or not any credit of a player remains based on credit data  320  which is stored in the RAM  226 . In a case where at least one credit of the player remains, the input/credit check processing part  300  invokes the random number generation processing part  302 . 
     Subsequently, the random number generation processing part  302  generates random numbers, and the symbol determination processing part  304  uses these random numbers. In the present embodiment, the random number generation processing part  302  generates five random numbers. Each of the five random numbers is used in each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E. 
     After all of the five random numbers have been extracted, the symbol determination processing part  304  determines to-be-stopped symbols of each of the reels  52 A,  52 B,  52 C,  52 D, and  52 E with reference to the symbol code determination table. The symbol determination processing part  304  determines five to-be-stopped symbols of the reels  52 A,  52 B,  52 C,  52 D, and  52 E and causes the to-be-stopped symbols to appear in the display window  56  of the symbol display unit  40  with respect to the respective reels  52 A,  52 B,  52 C,  52 D, and  52 E. 
     In particular, with reference to a mode flag  322  stored in the RAM  226 , the symbol determination processing part  304  checks the current game mode. Processing of determining symbols in the basic game is different from processing of determining symbols in the free games. In the basic game, the symbol determination processing part  304  determines symbols by using a given symbol code determination table in accordance with a given procedure with random numbers. On the other hand, in the free games, the symbol determination processing part  304  continuously changes a symbol code determination table with respect to each of the unit games and alters processing of determining symbols. By continuously changing the symbol code determination table, in accordance with the progress of the free games, the number of winning combinations including at least one specific symbol can be increased. The number of free games which can be executed in a single set of free games is limited to a predetermined number, for example, eight. In order to limit the number of free games, the game counter processing part  306  counts the number of free games which have already been executed in the single set of free games and the number of remaining free games in the single set of free games. Values in a number-of-free-game counter  324  are stored in the RAM  226 . The game counter processing part  306  may belong to the symbol determination processing part  304 . 
     The reel control processing part  308  controls the reel assembly  50  by supplying stop position information according to the determined symbols. Thus, the reels  52 A,  52 B,  52 C,  52 D, and  52 E are spun, and subsequently, the spun reels are stopped at positions which are specified according to the stop position information. In other words, the symbols scroll with the spinning of the reels  52 A,  52 B,  52 C,  52 D, and  52 E. Next, the reel control processing part  308  stops the reels  52 A,  52 B,  52 C,  52 D, and  52 E such that the determined symbols are rearranged at central positions in a vertical direction in the display window  56  of the symbol display unit  40 . 
     The winning determination processing part  310  determines whether or not a predetermined winning combination is established by the rearranged symbols. In a case where the winning combination is established by the rearranged symbols, the effect control processing part  312  controls the symbol display unit  40  and other devices. As the other devices, the speaker  112 , the lamp  114 , a video display unit  110 , and the like are included. As effects, effects by video and audio and effects by changes in the backlight and illumination are included. In addition, the payout processing part  314  determines the amount of payout in accordance with the established winning combination, and the amount of payout is awarded to a player. 
     In addition, each time a unit game is terminated, the game mode determination processing part  316  determines a game mode of a next unit game. In a case where a trigger event has occurred by the rearranged symbols, the game mode determination processing part  316  changes the game mode from the basic game mode to the free game mode. On the other hand, in a case where a termination condition has been met, the game mode determination processing part  316  changes the game mode from the free game mode to the basic game mode. In a case other than the above-mentioned cases the game mode determination processing part  316  maintains an immediately preceding game mode. The processing by the game mode determination processing part  316  may be executed by the winning determination processing part  310 . 
     &lt;Payline&gt; 
       FIG. 9  shows an example of a payline definition table defining paylines employed in the gaming machine  10 . In the gaming machine  10 , five paylines are set for a symbol matrix. The payline definition table shows that any of the first to third rows each constitutes a payline with respect to the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E. 
     For example, this table shows that a payline “No. 1” is constituted of a second row of the first reel  52 A (first column), a second row of the second reel  52 B (second column), a second row of the third reel  52 C (third column), a second row of the fourth reel  52 D (fourth column), and a second row of the fifth reel  52 E (fifth column). 
     In addition, this table shows that a payline “No. 2” is constituted of a first row of the first reel  52 A (first column), a first row of the second reel  52 B (second column), a first row of the third reel  52 C (third column), a first row of the fourth reel  52 D (fourth column), and a first row of the fifth reel  52 E (fifth column). 
     In addition, this table shows that a payline “No. 3” is constituted of a third row of the first reel  52 A (first column), a third row of the second reel  52 B (second column), a third row of the third reel  52 C (third column), a third row of the fourth reel  52 D (fourth column), and a third row of the fifth reel  52 E (fifth column). 
     In addition, this table shows that a payline “No. 4” is constituted of a first row of the first reel  52 A (first column), a second row of the second reel  52 B (second column), a third row of the third reel  52 C (third column), a second row of the fourth reel  52 D (fourth column), and a first row of the fifth reel  52 E (fifth column). 
     In addition, this table shows that a payline “No. 5” is constituted of a third row of the first reel  52 A (first column), a second row of the second reel  52 B (second column), a first row of the third reel  52 C (third column), a second row of the fourth reel  52 D (fourth column), and a third row of the fifth reel  52 E (fifth column). 
     Each of the paylines can be activated in accordance with a player&#39;s selection. However, all of the 5 paylines can be activated, regardless of whatsoever the amount of bets or the player&#39;s selection may be. A total number of paylines can be changed in accordance with a size of the symbol matrix, and other paylines can be appropriately set. 
     &lt;Symbol Determination Table for Basic Game&gt; 
       FIG. 10  shows an example of a symbol determination table for the basic game in the first embodiment. 
     In this example, the symbol determination table for the basic game is shown as a table defining the symbols in the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E, symbol arrangement, and probabilities with which the respective symbols appear. The symbol determination table defines probabilities with which the symbols on each of the reels appear on a predetermined row of the symbol matrix (for example, a second row). 
     In this symbol determination table, weights appearing on the predetermined row are associated with the respective symbols of each of the reels, whereby the probabilities with which the symbols appear are defined. For example, with respect to a 2BAR symbol of a code number 00 on the first reel  52 A, the weight is set to “6”, and the appearance probability is set to 6/284 (although the 284 in the lowest row is a total weight, said row is merely indicated for the sake of convenience and does not need to be included in the symbol determination table). 
     &lt;Payout Table&gt; 
       FIG. 11  shows an example of a payout table in the first embodiment. 
     The payout table briefly shows a relationship between winning combinations and the respective payouts. This table shows how much a corresponding payout is in a case where any combination of symbols is displayed on the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E on a defined payline. In this case, the symbols other than CHERRY symbols and BONUS symbols will be described. In a case where a part of a symbol combination may be any symbol, it is defined as (ANY). Although (ANY) symbols are set on the forth reel and the fifth reel for the sake of convenience, in the present embodiment, in a case where the (ANY) symbols are respectively displayed on the fourth reel and the fifth reel, it is denoted that any two symbols among the symbols on the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E may be arbitrary symbols, and in a case where an (ANY) symbol is displayed on only the fifth reel, it is denoted that any one symbol among the symbols on the first to fifth reels may be an arbitrary symbol. 
     In addition, in a case where “1BAR/2BAR/3BAR” symbols or the like are shown, it is indicated that when any one of these three symbols is displayed, a condition is met. 
     With respect to the CHERRY symbols and the BONUS symbols, it is not required for any combination of these symbols to be displayed on a payline, and when a predetermined number or more of these symbols are displayed in the display window  56 , each predetermined payout is awarded. In the payout table, payouts corresponding to the numbers of the CHERRY symbols or the BONUS symbols displayed in the display window  56  are shown. 
     In the gaming machine  10 , the winning determination processing part  310  refers to the payout table each time a unit game is executed and determines whether or not a winning combination is established on a payline or whether or not the predetermined number or more of winning symbols are displayed in the display window  56 . In a case where it is determined that a winning combination defined in the payout table is included on one of the paylines or the predetermined number or more of winning symbols are displayed in the display window  56 , the winning determination processing part  310  detects the winning combination or the winning symbols and with reference to the payout table, checks a payout. 
     The payout processing part  314  pays out the determined amount of a payout. On the other hand, in a case where it is determined that a winning combination is not established by the symbols that have appeared on a payline and that the predetermined number or more of winning symbols are not displayed in the display window  56 , the winning determination processing part  310  determines that a game outcome is the so-called “losing”. The profit by the payout is awarded to a player by paying coins to the coin tray  92  or alternatively, adding credits equivalent to the amount of a payout. 
     &lt;Game State Transition&gt; 
       FIG. 12  is a diagram showing a pattern of state transition in the gaming machine  10 . 
     The gaming machine  10  executes two kinds of games: the basic game and the free games as a feature game. In the gaming machine  10 , the basic game is executed as a main game, and when in the basic game, a trigger (event) has occurred, the game shifts to the feature game. 
     In the first embodiment, a condition on which the trigger occurs is that in the display window  56  of the symbol display unit  40 , the BONUS symbols have been rearranged (three or more BONUS symbols have been rearranged) on a predetermined condition. Of course, other condition may be set as the condition on which the trigger occurs. 
     As can be understood from  FIG. 12 , in the basic game, a unit game is repeated until the BONUS symbols have been rearranged in the display window  56  of the symbol display unit  40  on the predetermined condition. In this basic game, when a combination of the symbols rearranged on a payline matches any winning combination shown in the payout table, coins whose number is in accordance with a payout for that combination are paid out. In addition, when in the display window  56 , the predetermined number or more of the predetermined winning symbols have been rearranged, coins whose number is in accordance with a payout associated with the number of the rearranged winning symbols are paid out. 
     In the free games, a unit game similar to the unit game in the basic game is repeatedly executed without consuming any gaming media such as medals. When three or more BONUS symbols have been displayed, the number of free games is increased and when the number of remaining free games becomes “0” (that is, a value on the number-of-free-game counter  324  is zero), the game is terminated and the game reverts to the basic game. 
     In the first embodiment, the number of free games upon starting the free games is set to 10. In addition, in the free games, when in the display window  56  of the symbol display unit  40 , the three or more BONUS symbols have been rearranged, the number of free games to be further added is determined to be five, and the five free games are added to the number of free games remaining at that time. 
     [Contents of Programs] 
     Next, with reference to  FIG. 13  to  FIG. 17 , programs executed by the gaming machine  10  will be described. 
     &lt;Main Control Processing&gt; 
     First, with reference to  FIG. 13 , main control processing will be described.  FIG. 13  is a flowchart of the main control processing in the gaming machine  10  according to the first embodiment of the present invention. 
     First, when power is supplied to the gaming machine  10 , the main CPU  222  reads out the authenticated game program and game system program from the memory card  210  via the game board  200  and writes the read-out programs into the RAM  226  (step S 11 ). 
     Next, the main CPU  222  conducts at-one-game-termination initialization processing (step S 12 ). For example, data such as the number of BETs and the symbols determined by conducting a lottery, which becomes unnecessary in the workspace of the RAM  226  each time one game is played, is cleared. 
     Next, the main CPU  222  conducts coin entry/start check processing to be described later with reference to  FIG. 14  (step S 13 ). In this processing, input check of any BET button and the spin button or the like is conducted. 
     Next, the main CPU  222  conducts symbol lottery processing for the basic game to be described later with reference to  FIG. 15  (step S 14 ). In this processing, determination of to-be-stopped symbols based on random number values for determination of symbols is conducted. 
     Next, the effect control processing part  312  operatively executed by the main CPU  222  conducts content-of-effect determination executing processing (step S 15 ). The main CPU  222  extracts random number values for effects, determines any of a plurality of predetermined contents of effects by conducting a lottery, and executes the contents of effects at the timing of the determined contents of effects. For example, the main CPU  222  conducts control in such a manner that a video image for effects is displayed on the video display unit  110 , audio is outputted by the speaker  112 , the lamp  114  is lit, and effect processing is applied to these contents, etc. 
     Next, the main CPU  222  conducts symbol display control processing to be described later with reference to  FIG. 16  (step S 16 ). In this processing, scrolling of symbol arrays of each of the reels is started, to-be-stopped symbols determined in the symbol lottery processing for the basic game at step S 14  are stopped at their predetermined positions. In addition, light emission control for each of the reels is conducted based on the values of the BONUS symbols which are determined in the symbol lottery processing for the basic game at step S 14 . 
     Next, the main CPU  222  conducts number-of-payout determination processing to be described later with reference to  FIG. 17  (step S 17 ). In this processing, in the basic game, determination of the number of payout based on the payout table ( FIG. 11 ) is conducted according to a combination of symbols which are displayed on a payline, and the determined number of payout is stored in the number-of-payout storage region which is provided in the RAM  226  (the number-of-payout counter  321 ). 
     Next, the main CPU  222  determines whether or not a feature game trigger is established (step S 18 ). When the main CPU  222  determines that the feature game trigger is established (for example, the main CPU  222  determines that the feature game trigger is established in a case where the game mode is a feature game mode), the main CPU  222  conducts feature game processing to be described later with reference to  FIG. 18  (step S 19 ). 
     Next, after the processing at step S 19 , or at step S 18 , when the main CPU  222  determines that the feature game trigger is not established the main CPU  222  conducts payout processing (step S 20 ). The main CPU  222  adds a value stored in the number-of-payout storage region (the number-of-payout counter  321 ) to a value stored in the number-of-credit storage region provided in the RAM  226  (the number-of-credit counter  320 ). One or more coins according to the number-of-payout counter  321  may be ejected from the coin payout opening by controlling the driving of the hopper  242 . In addition, a ticket having a barcode attached thereon in which the number-of-payout counter  321  is recorded may be issued by controlling the driving of the ticket printer  120 . After this processing has been conducted, the mode flag and the symbol value storage region or the like are cleared, and the game shifts to step S 12 . 
     &lt;Coin Entry/Start Check Processing&gt; 
     Next, with reference to  FIG. 14 , coin entry/start check processing will be described.  FIG. 14  is a flowchart of the coin entry/start check processing in the gaming machine  10  according to the first embodiment of the present invention. 
     First, with the use of the input/credit check processing part  300  operatively executed by the main CPU  222 , the main CPU  222  determines whether or not coin entry is detected by the coin counter  232  (step S 41 ). When the main CPU  222  determines that the coin entry is detected, the main CPU  222  adds a value of the number of the entered coins to a value stored in the number-of-credit storage region (the number-of-credit counter  320 ) (step S 42 ). In addition to the coin entry, it is determined by the bill validator  246  whether or not bill entry is detected, and when it is determined that the bill entry is detected, a value corresponding to the bill may be added to the number-of-credit counter  320 . 
     After step S 42  or at step S 41 , when the main CPU  222  determines that the coin entry is not detected, the main CPU determines whether or not the number-of-credit counter  320  is set to 0 (step S 43 ). When the main CPU  222  determines that the number-of-credit counter  320  is not set to 0, the main CPU  222  permits acceptance of operation of any BET button (step S 44 ). 
     Next, the main CPU  222  determines whether or not the operation of any BET button is detected (step S 45 ). When the main CPU  222  detects that any BET button is pressed by a player with use of the BET switch, the main CPU  222  adds a value stored in the number-of-BET storage region which is provided in the RAM  226  (the number-of-BET counter  325 ), based on a kind of the BET button, and subtracts on the number-of-credit counter  320  (step S 46 ). 
     Next, the main CPU  222  determines whether or not a value on the number-of-BET counter  325  is a maximum (step S 47 ). When the main CPU  222  determines that the value on the number-of-BET counter  325  is the maximum, the main CPU  222  disables updating of the number-of-BET counter  325  (step S 48 ). When the main CPU  222  determines that the value on the number-of-BET counter  325  is not the maximum subsequent to step S 48  or in step S 47 , the main CPU  222  permits acceptance of operation of the spin button (step S 49 ). 
     After step S 49  or at step S 45 , when the main CPU  222  determines that the operation of the BET button is not detected, or alternatively, at step S 43 , when the main CPU  222  determines the number-of-credit counter  320  is set to 0, the main CPU  222  determines whether or not operation of the spin button is detected (step S 50 ). When the main CPU  222  determines that the operation of the spin button is detected, the game shifts to step S 41 . 
     When the main CPU  222  determines that the operation of the spin button is detected, the main CPU  222  finishes the coin entry/start check processing. 
     &lt;Symbol Lottery Processing for Basic Game&gt; 
     Next, with reference to  FIG. 15 , symbol lottery processing for the basic game will be described.  FIG. 15  is a flowchart of the symbol lottery processing for the basic game in the gaming machine  10  according to the first embodiment of the present invention. 
     First, the number-of-random generating processing part  302  operatively executed by the main CPU  222  extracts random number values for determination of symbols (step S 111 ). Next, the symbol determination processing part  304  operatively executed by the main CPU  222  determines the to-be-stopped symbols of each of the reels by conducting a lottery (step S 112 ). The main CPU  222  conducts the lottery with respect to each of the reels (first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E) and determines any of 22 symbols (code numbers “00” to “21”) as the to-be-stopped symbols, based on the symbol determination table for the basic game (shown in  FIG. 10  ( FIG. 31  in the second embodiment and  FIG. 46  in the third embodiment)). At this time, the probabilities with which any of the 22 symbols (code numbers “00” to “21”) appear are determined in accordance with the weights in the symbol determination table. 
     Next, the main CPU  222  stores the determined to-be-stopped symbols of each of the reels in the symbol storage region that is provided in the RAM  226  (step S 113 ). Next, the winning determination processing part  310  operatively executed by the main CPU  222  determines a winning combination based on a combination of the symbols which are stored in the symbol storage region with reference to the payout table (shown in  FIG. 11  ( FIG. 32  in the second embodiment and  FIG. 47  in the third embodiment)) (step S 114 ). The main CPU  222  determines whether or not a combination of the symbols displayed on a payline by each of the reels matches any combination of the symbols defined in the payout table or whether or not the predetermined number or more of predetermined winning symbols defined in the payout table have been rearranged in the display window  56  and determines a winning combination. 
     &lt;Symbol Display Control Processing&gt; 
     Next, with reference to  FIG. 16 , symbol display control processing will be described.  FIG. 16  is a flowchart of the symbol display control processing in the gaming machine  10  according to the first embodiment of the present invention. 
     First, the reel control processing part  308  operatively executed by the main CPU  222  transmits a spinning control signal to each of the reel assemblies (not shown), and the reel driver  264  of each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E supplies power to each of the reel motors  272  and then spins each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E. In response thereto, the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E respectively start spinning, and the symbol arrays assigned to the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E scroll in the display window  56  of the symbol display unit  40  (step S 131 ). 
     Next, the reel control processing part  308  operatively executed by the main CPU  222  conducts reel stop control (step S 132 ). The spinning control signal includes information relevant to a stop position of each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E, which is obtained from the to-be-stepped symbols in each of the reels stored in the symbol storage region. The reel driver  264  of each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E controls the reel motor  272  and stops each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E at the position which is indicated by the spinning control signal. In this manner, the reel motor  272  constituted of a stepping motor is stopped at a desired position, and scrolling of the symbol arrays is stopped such that the to-be-stopped symbols are located in the second row of the symbol matrix which is formed in the display window  56 . In the first embodiment, the reels are stopped in the order of the first reel  52 A, the second reel  52 B, the third reel  52 C, the fourth reel  52 D, and the fifth reel  52 E. 
     Lastly, the symbol display control processing is finished and the flow of execution reverts to the main processing. 
     &lt;Number-of-Payout Determination Processing&gt; 
     Next, with reference to  FIG. 17 , number-of-payout determination processing will be described.  FIG. 17  is a flowchart of the number-of-payout determination processing in the gaming machine  10  according to the first embodiment of the present invention. 
     With reference to the symbol storage region and the payout table (shown in  FIG. 11  ( FIG. 32  in the second embodiment and  FIG. 47  in the third embodiment)), the number-of-payout is determined based on a payout corresponding to any winning combination in the basic game (step S 151 ). For example, when on the paylines across the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E, SEVEN symbols are displayed on all of the reels, the winning combination is established as “SEVEN”, and based on the corresponding payout “500” (refer to the payout table shown in  FIG. 11 ), the number of a payout is determined as “500”. It is to be noted that when “Losing” is established, the number of a payout is determined as “0”. 
     Subsequent to step S 151 , the payout processing part  314  operatively executed by the main CPU  222  stores the determined number of a payout in the number-of-payout counter  321  of the number-of-payout storage region (step S 152 ). Upon having conducted this processing, the number-of-payout determination processing is finished. 
     &lt;Feature Game Processing&gt; 
     Next, with reference to  FIG. 18 , feature game processing will be described.  FIG. 18  is a flowchart of the feature game processing in the gaming machine  10  according to the first embodiment of the present invention. 
     This processing is invoked in a case where it is determined that a feature game trigger is established in the main control processing shown in  FIG. 13 . First, the effect control processing part  312  operatively executed by the main CPU  222  conducts control to display an effect video image on the video display unit  110  in order to conduct effects related to the start of a feature game (step S 171 ). 
     Next, the game counter processing part  306  operatively executed by the main CPU  222  sets the number of free games as 10 to the value stored in the number-of-free-game storage region (the number-of-free-game counter  324 ) (step S 172 ). Subsequently, the game mode determination processing part  316  operatively executed by the main CPU  222  sets the game mode to the free game mode, and as described later, a unit game which is similar to that in the basic game is repeatedly conducted at 10 times (there is a case where the number of free games may be increased based on the later-described condition) according to the determined number of free games. 
     Next, the main CPU  222  conducts symbol lottery processing for the free games, later described with reference to  FIG. 19  (step S 173 ). In this processing, to-be-stopped symbols are determined based on the later-described first to tenth symbol determination tables for the free games and random number values for the determination of symbols. 
     Next, the effect control processing part  312  operatively executed by the main CPU  222  conducts content-of-effect determination executing processing (step S 174 ). The main CPU  222  extracts effect random number values, determines any of a plurality of the predetermined contents of effects by conducting a lottery, and executes the contents of effects at the timing of the determined contents of effects. For example, an effect video image is displayed on the video display unit  110 , audio (such as background music (BGM)) is outputted by the speaker  112 , the lamp  114  is lit, and effect processing is applied to these elements, etc., thereby conducting control of a display mode or the like. 
     Next, the main CPU  222  conducts symbol display control processing which is similar to that in the main control processing shown in  FIG. 16  (step S 175 ). It is to be noted that the symbol display control processing at step S 175  can be conducted prior to or in parallel with the execution of the contents of effects at step S 174 . Next, the main CPU  222  conducts number-of-payout determination processing which is similar to that in the main control processing shown in  FIG. 16  (step S 176 ). 
     Subsequently, the game counter processing part  306  operatively executed by the main CPU  222  subtracts “1” from a value on the number-of-free-game counter  324  in response to the termination of one free game (step S 177 ). The main CPU  222  determines whether or not the feature game trigger is established as a result of the symbol lottery processing for the free games at step S 173  (step S 178 ), and if the feature game trigger is established (retrigger), the main CPU  222  turns on a retrigger flag stored in a predetermined region of the RAM  226  (step S 179 ). Once this retrigger flag is turned on since the start of the free games, even if the retrigger is established again, the retrigger flag remains on until the value on the number-of-free-game counter  324  becomes zero and the free games are terminated. Thus, as in the later-described symbol lottery processing for the free games shown in  FIG. 19 , the processing executed before establishing the first retrigger and the processing executed after establishing the first retrigger are different from each other. Next, the game counter processing part  306  operatively executed by the main CPU  222  adds five as the number of free games to be newly added by the retrigger to the value stored in the number-of-free-game region (number-of-free-game counter  324 ) (step S 180 ). 
     Next, the main CPU  222  determines whether or not the number-of-free-game counter  324  is set to 0 in a case where no feature game is established or in a case where the processing at step S 180  is finished (step S 181 ). When the number-of-free-game counter  324  is not set to 0, the main CPU  222  shifts the processing to step S 173  in order to conduct a new free game. When the number-of-free-game counter  324  is set to 0, the main CPU  222  clears the retrigger flag (step S 182 ) and finishes the feature game processing. 
     &lt;Symbol Lottery Processing for Free Games&gt; 
     Next, with reference to  FIG. 19 , symbol lottery processing for the free games will be described.  FIG. 19  is a flowchart of the symbol lottery processing for the free games in the gaming machine  10  according to the first embodiment of the present invention. 
     First, the main CPU  222  determines whether or not the retrigger flag is on (step S 191 ). When the retrigger flag is off, that is, when the retrigger is not established, with reference to a symbol determination table first selection table ( FIG. 20A ), the main CPU  222  selects one symbol determination table from among the first to sixth symbol determination tables for the free games (step S 192 ). On the other hand, when the retrigger flag is on, that is, when the retrigger is established at one or more times, with reference to a symbol determination table second selection table ( FIG. 20B ), the main CPU  222  one symbol determination table from among the fifth to tenth symbol determination tables for the free games (step S 193 ). 
     In the symbol determination table first selection table shown in  FIG. 20A , weights corresponding to the seventh to tenth symbol determination tables for the free games among the first to tenth symbol determination tables for the free games are defined as zero. Accordingly, one symbol determination table is selected from among the first to sixth symbol determination tables for the free games. Here, in the first to sixth symbol determination tables for the free games ( FIG. 21  to  FIG. 26 ), probabilities with which the respective symbols appear are set so as to allow the retrigger to be easily established. More specifically, a probability with which the three or more BONUS symbols are rearranged in the display window  56  is set to be high (higher than a predetermined probability). Thus, it is made possible for the retrigger to be easily established when the retrigger has not been established. 
     Therefore, a player can play the games while expecting the addition of the number of free games since the start of the free games. 
     On the other hand, in the symbol determination table second selection table shown in  FIG. 20B , weights corresponding to the first to fourth symbol determination tables for the free games among the first to tenth symbol determination tables for the free games are defined as zero. Accordingly, one symbol determination table is selected from among the fifth to tenth symbol determination tables for the free games. Here, in the seventh to tenth symbol determination tables ( FIG. 27  to  FIG. 30 ) among the fifth to tenth symbol determination tables for the free games, probabilities with which the respective symbols appear are set so as to allow the retrigger to be less easily established. More specifically, a probability with which the three or more BONUS symbols are rearranged in the display window  56  is set to be low (lower than a predetermined probability). Thus, it is made possible for the retrigger to be less easily established when the retrigger has once been established. 
     Therefore, the excessive addition of the free games for a player can be prevented. In addition, even after free games have once been added to the number of games, although the probability with which the retrigger is established is lowered, a player can play the games while further expecting the addition of the free games to the number of games. 
     Further, each of the first to tenth symbol determination tables for the free games is selected by conducting a lottery for each game. In addition, the probabilities, with which the three or more BONUS symbols are rearranged in the display window  56 , in the respectively selected symbol determination tables are set to be different from one another. Accordingly, in the case where the three or more BONUS symbols are easily rearranged in the display window  56  as well as in the case where the three or more BONUS symbols are less easily rearranged in the display window  56 , the variation of said probabilities is increased, thus allowing the games to be prevented from becoming monotonous. 
     Further, in the first and tenth symbol determination tables for the free games ( FIG. 21  and  FIG. 30 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 5” payline. In the second and seventh symbol determination tables for the free games ( FIG. 22  and  FIG. 27 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 1” payline. In the third and eighth symbol determination tables for the free games ( FIG. 23  and  FIG. 28 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 2” payline. In the fourth and ninth symbol determination tables for the free games ( FIG. 24  and  FIG. 29 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 3” payline. In the fifth symbol determination table for the free games ( FIG. 25 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 4” and “No. 5” paylines. In the sixth symbol determination table for the free games ( FIG. 26 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 4” payline. Thus, it is made possible to vary the paylines for each of the free games, on which the SEVEN symbols are easily rearranged. 
     Accordingly, in the free games, in accordance with the selected symbol determination table, the payline on which the SEVEN symbol combination is established is varied each time the game is played. Thus, diversity can be imparted to the patterns, in each of which the winning obtained by the SEVEN symbol combination is established. 
     Next, the random number generation processing part  302  operatively executed by the main CPU  222  extracts random number values for the determination of symbols (step S 194 ). The symbol determination processing part  304  operatively executed by the main CPU  222  determines to-be-stopped symbols of each of the reels by conducting a lottery based on the random number values extracted at step S 194  (step S 195 ). The main CPU  222  conducts the lottery with respect to each of the reels (the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E) and based on the one symbol determination table selected at step S 192  or step S 193  from among the first to tenth symbol determination tables for the free games ( FIG. 21  to  FIG. 30 ), determines any of 22 symbols (code numbers “00” to “21”) as the to-be-stopped symbols. At this time, the appearance probabilities of the 22 symbols (code numbers “00” to “21”) are in accordance with the weights in each of the symbol determination tables. 
     Next, the main CPU  222  stores the to-be-stopped symbols of each of the reels in the symbol storage region provided in the RAM  226  (step S 196 ). Next, with reference to the payout table ( FIG. 11 ), the winning determination processing part  310  executed by the main CPU  222  determines a winning combination based on a combination of the symbols stored in the symbol storage region (step S 197 ). The main CPU  222  determines whether or not a combination of symbols displayed on a payline by each of the reels matches any symbol combination defined in the payout table or whether or not the predetermined number or more of the predetermined winning symbols defined in the payout table are rearranged in the display window  56 , thereby determining a winning combination. 
     In the first embodiment, although the number of free games which is set immediately after shifting to the free games is set to 10, the number thereof is not limited thereto and may be less than 10 or exceed 10. In addition, although the number of additional games to be added when the retrigger is established is five, the number thereof is not limited thereto and the number thereof may be less than five or exceed five. 
     In addition, in the first embodiment, although the condition on which the retrigger is established is that the three or more BONUS symbols are rearranged in the display window  56 , the condition is not limited thereto. The condition may be that any symbols other than the BONUS symbols are rearranged therein, or may be that, for example, four or more symbols are rearranged in the display window  56 . 
     Second Embodiment 
     Hereinbefore, the first embodiment is described. Hereinafter, a second embodiment will be described. It is to be noted that the description regarding parts of a configuration in common with those of the first embodiment is omitted and only parts of the configuration differing from those of the first embodiment will be described with reference to the accompanying drawings. 
     &lt;Symbol Determination Table for Basic Game&gt; 
       FIG. 31  shows an example of a symbol determination table for a basic game in the second embodiment. In said table, arrangement of symbols on each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E and values of corresponding weights are different from those in the first embodiment. However, a basic function thereof is the same as that of the symbol determination table for the basic game ( FIG. 10 ) in the first embodiment. 
     &lt;Payout Table&gt; 
       FIG. 32  shows an example of a payout table in the second embodiment. In said table, kinds of symbols are partly different from those in the first embodiment. However, a basic function thereof is the same as that of the payout table ( FIG. 11 ) in the first embodiment. 
     &lt;Game State Transition&gt; 
       FIG. 33  is a diagram showing a pattern of state transition in a gaming machine  10  in the second embodiment. 
     The gaming machine  10  executes two kinds of games: a basic game and free games as a feature game. In the gaming machine  10 , the basic game is executed as a main game, and when in the basic game, a trigger (event) has occurred, the game shifts to the feature game. 
     In the second embodiment, a condition on which the trigger occurs is that predetermined symbols have been rearranged on a payline defined in the payline definition table ( FIG. 9 ) on a predetermined condition. This predetermined condition is that a combination of symbols rearranged on a payline is a combination of SEVEN symbols or BELL symbols. Of course, other condition may be set as the condition on which the trigger occurs. 
     As can be understood from  FIG. 33 , in the basic game, a unit game is repeated until the predetermined symbols have been rearranged on a payline defined in the payline definition table ( FIG. 9 ) on the predetermined condition. In this basic game, when a combination of the symbols rearranged on a payline matches any winning combination shown in the payout table, coins whose number is in accordance with a payout for that combination are paid out. In addition, when in the display window  56 , the predetermined number or more of the predetermined winning symbols have been rearranged, coins whose number is in accordance with a payout associated with the number of the rearranged winning symbols are paid out. 
     In the free games, a unit game similar to the unit game in the basic game is repeatedly executed without consuming any gaming media such as medals. When a COIN symbol is rearranged in a region corresponding to the fourth reel  52 D or the fifth reel  52 E in the display window  56  (a particular condition is established), the game is terminated and the game reverts to the basic game. 
     In the second embodiment, upon starting the free games, the number of free games is not set. The free games are continued until the COIN symbol is rearranged in the region corresponding to the fourth reel  52 D or the fifth reel  52 E in the display window  56 . However, as described later, when the number of free games which have already been played is three or less, the COIN symbol is set so as not to be rearranged. Accordingly, a player can play at least three free games. 
     &lt;Feature Game Processing&gt; 
     Next, with reference to  FIG. 34 , feature game processing will be described.  FIG. 34  is a flowchart of the feature game processing in the gaming machine  10  according to the second embodiment of the present invention. 
     This processing is invoked in a case where it is determined that a feature game trigger is established in the main control processing shown in  FIG. 13 . First, the effect control processing part  312  operatively executed by the main CPU  222  conducts control to display an effect video image on the video display unit  110  in order to conduct effects related to the start of a feature game (step S 211 ). 
     Next, the game counter processing part  306  operatively executed by the main CPU  222  sets zero to a value stored in the number-of-free-game storage region (the number-of-free-game counter  324 ) (step S 212 ). In the second embodiment, the number-of-free-game counter  324  indicates the number of free games which a player has already played. Subsequently, the game mode determination processing part  316  operatively executed by the main CPU  222  sets the game mode to the free game mode, and as described later, a unit game which is similar to that in the basic game is repeatedly conducted until the COIN symbol is rearranged in the part corresponding to the fourth reel  52 D or the fifth reel  52 E in the display window  56 . 
     Next, the main CPU  222  conducts symbol lottery processing for the free games, later described with reference to  FIG. 35  (step S 213 ). In this processing, to-be-stopped symbols are determined based on the later-described first to ninth symbol determination tables for the free games and random number values for the determination of symbols. 
     Next, the effect control processing part  312  operatively executed by the main CPU  222  conducts content-of-effect determination executing processing (step S 214 ). The specific processing which the main CPU  222  executes is the same as that in the first embodiment. 
     Next, the main CPU  222  conducts symbol display control processing which is similar to that in the main control processing shown in  FIG. 16  (step S 215 ). It is to be noted that the symbol display control processing at step S 215  can be conducted prior to or in parallel with the execution of the contents of effects at step S 214 . Next, the main CPU  222  conducts number-of-payout determination processing which is similar to that in the main control processing shown in  FIG. 16  (step S 216 ). 
     Next, the main CPU  222  determines whether or not a winning combination of the COIN symbols appears, that is, whether or not the COIN symbol is rearranged in the region corresponding to the fourth reel  52 D or the fifth reel  52 E in the display window  56  (step S 217 ). When the winning combination of the COIN symbols does not appear, the main CPU  222  shifts the processing to step S 213  in order to conduct a new free game. When the winning combination of the COIN symbols appears, the main CPU  222  finishes the feature game processing. 
     &lt;Symbol Lottery Processing for Free Games&gt; 
     Next, with reference to  FIG. 35 , symbol lottery processing for the free games will be described.  FIG. 35  is a flowchart of the symbol lottery processing for the free games in the gaming machine  10  according to the second embodiment of the present invention. 
     First, the game counter processing part  306  operatively executed by the CPU  222  adds one to the number-of-free-game counter  324  (step S 231 ). Next, the main CPU  222  determines whether or not a value on the number-of-free-game counter  324  is four or more (step S 232 ). When a value on the number-of-free-game counter  324  is three or less, that is, when the number of free games which have already been played is three or less, with reference to a symbol determination table first selection table ( FIG. 36A ), the main CPU  222  selects one symbol determination table from among the first to ninth symbol determination tables for the free games (step S 233 ). On the other hand, when a value on the number-of-free-game counter  324  is four or more, that is, when the number of free games which have already been played is four or more, with reference to a symbol determination table second selection table ( FIG. 36B ), the main CPU  222  selects one symbol determination table from among the first to ninth symbol determination tables for the free games (step S 234 ). 
     Here, the first to ninth symbol determination tables for the free games ( FIG. 37  to  FIG. 45 ) in the second embodiment will be described. In the first symbol determination table for the free games ( FIG. 37 ), appearance probabilities of the respective symbols are set such that the BELL symbols are easily rearranged on the “No. 1” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the BELL symbols are invariably rearranged on the “No. 1” payline. Therefore, a ready-to-win combination of the BELL symbols is invariably established. 
     In the second symbol determination table for the free games ( FIG. 38 ), appearance probabilities of the respective symbols are set such that the BELL symbols are easily rearranged on the “No. 4” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the BELL symbols are invariably rearranged on the “No. 4” payline. Therefore, a ready-to-win combination of the BELL symbols is invariably established. 
     In the third symbol determination table for the free games ( FIG. 39 ), appearance probabilities of the respective symbols are set such that the BELL symbols are easily rearranged on the “No. 5” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the BELL symbols are invariably rearranged on the “No. 5” payline. Therefore, a ready-to-win combination of the BELL symbols is invariably established. 
     In the fourth symbol determination table for the free games ( FIG. 40 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 1” or “No. 5” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the SEVEN symbols are invariably rearranged on the “No. 1” or “No. 5” payline. Therefore, a ready-to-win combination of the SEVEN symbols is invariably established. 
     In the fifth symbol determination table for the free games ( FIG. 41 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 1” or “No. 4” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the SEVEN symbols are invariably rearranged on the “No. 1” or “No. 4” payline. Therefore, a ready-to-win combination of the SEVEN symbols is invariably established. 
     In the sixth symbol determination table for the free games ( FIG. 42 ), appearance probabilities of the respective symbols are set such that the COIN symbol is likely to be rearranged in the region corresponding to the fourth reel  52 D in the display window  56  and the COIN symbol is likely to be rearranged in the region corresponding to the fifth reel  52 E in the display window  56 . Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the SEVEN symbols are invariably rearranged on the “No. 1”, “No. 4”, or “No. 5” payline. Therefore, a ready-to-win combination of the SEVEN symbols is invariably established. 
     In the seventh symbol determination table for the free games ( FIG. 43 ), appearance probabilities of the respective symbols are set such that the COIN symbol is likely to be rearranged in the region corresponding to the fourth reel  52 D in the display window  56  and the COIN symbol is likely to be rearranged in the region corresponding to the fifth reel  52 E in the display window  56 . Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the BELL symbols are invariably rearranged on the “No. 1”, “No. 4”, or “No. 5” payline. Therefore, a ready-to-win combination of the BELL symbols is invariably established. 
     In the eighth symbol determination table for the free games ( FIG. 44 ), appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the SEVEN symbols are invariably rearranged on the “No. 1”, “No. 4”, or “No. 5” payline. Therefore, a ready-to-win combination of the SEVEN symbols is invariably established. 
     In the ninth symbol determination table for the free games ( FIG. 45 ), appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the BELL symbols are invariably rearranged on the “No. 1”, “No. 4”, or “No. 5” payline. Therefore, a ready-to-win combination of the BELL symbols is invariably established. 
     As described above regarding the first to ninth symbol determination tables for the free games in the second embodiment, each payline on which the winning symbols are rearranged can be varied each time each of the free games is played. Thus, diversity can be imparted to patterns, in each of which the BELL or SEVEN winning combination is established. In addition, each payline on which the ready-to-win combination is established can be varied each time each of the free games is played. Thus, diversity can be imparted to patterns, in each of which the ready-to-win combination for the BELL or SEVEN winning combination is displayed. In addition, since the ready-to-win combination for the BELL or SEVEN winning combination is invariably established, a player can play the games while having a sense of expectation that the BELL or SEVEN winning combination could be established. 
     In the symbol determination table first selection table shown in  FIG. 36A , weights corresponding to the sixth, seventh, and ninth symbol determination tables for the free games among the first to ninth symbol determination tables for the free games are defined as zero. Accordingly, one symbol determination table is selected from among the first to fifth and eighth symbol determination tables for the free games. In addition, said symbol determination table first selection table is selected when the number of free games which have already been played is three or less. Therefore, when the number of free games which have already been played is three or less, there is no likelihood that the COIN symbol is rearranged in the region corresponding to each of the fourth reel  52 D and the fifth reel  52 E in the display window  56 . Therefore, it does not occur that the free games are terminated. Thus, a player can be provided with at least three free games. 
     On the other hand, in the symbol determination table second selection table shown in  FIG. 36B , weights corresponding to the sixth and ninth symbol determination tables for the free games among the first to ninth symbol determination tables for the free games are defined as zero. Accordingly, one symbol determination table is selected from among the first to fifth, seventh, and eighth symbol determination tables for the free games. In addition, said symbol determination table second selection table is selected when the number of free games which have already been played is four or more. Therefore, since when the number of free games which have already been played is four or more, the COIN symbol is likely to be rearranged in the region corresponding to the fourth reel  52 D in the display window  56  and the COIN symbol is likely to be rearranged in the region corresponding to the fifth reel  52 E in the display window  56 , there may be a case where the free games are terminated. Accordingly, a player can play the games while having a sense of expectation that the BELL or SEVEN winning combination could be established as well as a sense of tension that after the ready-to-win combination has been displayed, the COIN symbol would be rearranged and the free games could be thereby terminated. In addition, since the reels are stopped in the order from the first reel  52 A to the fifth reels  52 E, a player cannot recognize that the COIN symbol is rearranged and the free games are thereby terminated until either the fourth reel  52 D or the fifth reel  52 E is stopped. Thus, it is made possible to prevent a player from recognizing in an early stage while playing one of the free games that the free games are terminated. 
     During the free games, in all of the games, the sixth and the ninth symbol determination tables for the free games are not selected. The reason for this is that with respect to the sixth symbol determination table for the free games ( FIG. 42 ), it is heartless to a player, who is expecting that the SEVEN winning combination leading to a large payout could be established, to terminate the free games by rearranging the COIN symbol when the ready-to-win combination of the SEVEN symbols has been established. In addition, another reason for this is that with respect to the ninth symbol determination table for the free games ( FIG. 45 ), said table has the same function as that of each of the first to third symbol determination tables for the free games ( FIG. 37  to  FIG. 39 ). In other words, when each of the first to third symbol determination tables for the free games is selected, even after the ready-to-win combination of the BELL symbols is established, there is a case where the BELL winning combination is not established. However, the weights which the symbol determination table first and second selection table have are not limited to the above-described weights. For example, in the symbol determination table first selection table, the weight corresponding to the ninth symbol determination table for the free games may be defined as being larger than zero and the ninth symbol determination table for the free games may be thereby selected. In addition, in the symbol determination table second selection table, weights corresponding to the sixth and ninth symbol determination tables for the free games may be defined as being larger than zero and the sixth and ninth symbol determination tables for the free games may be thereby selected. In other words, when the number of free games which have already been played is four or more, the sixth symbol determination table for the free games may be likely to be selected and in all games of the free games, the ninth symbol determination table for the free games may be likely to be selected. 
     Next, the random number generation processing part  302  operatively executed by the main CPU  222  extracts random number values for the determination of symbols (step S 235 ). The symbol determination processing part  304  operatively executed by the main CPU  222  determines to-be-stopped symbols of each of the reels by conducting a lottery based on the random number values extracted at step S 235  (step S 236 ). The main CPU  222  conducts the lottery with respect to each of the reels (the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E) and determines any of 22 symbols (code numbers “00” to “21”) as the to-be-stopped symbols based on one symbol determination table selected at step S 233  or step S 234  among the first to ninth symbol determination tables for the free games ( FIG. 37  to  FIG. 45 ). At this time, appearance probabilities of the 22 symbols (code numbers “00” to “21”) are defined in accordance with the weights in the symbol determination table. 
     Next, the main CPU  222  stores the to-be-stopped symbols of each of the reels in a symbol storage region provided in the RAM  226  (step S 237 ). Next, with reference to the payout table ( FIG. 32 ), the winning determination processing part  310  operatively executed by the main CPU  222  determines a winning combination based on the combination of symbols stored in the symbol storage region (step S 238 ). The main CPU  222  determines whether or not a combination of symbols on a payline displayed by each of the reels matches any combination of symbols defined in the payout table or whether or not a predetermined number or more of predetermined winning symbols defined in the payout table are rearranged in the display window  56 , thereby determining a winning combination. 
     In the second embodiment, when the COIN symbol is rearranged in the region corresponding to the fourth reel  52 D or the fifth reel  52 E in the display window  56 , the free games are terminated. When the number of free games which have already been played is four or more, the seventh symbol determination table for the free games in which the COIN symbol is rearranged is likely to be selected. However, the case where said table is selected is not limited to the case where the number of free games which have already been played is four or more, and the case where said table is selected may be a case where the number of free games which have already been played is n or more (n is a natural number excluding four). 
     In addition, in the second embodiment, the free games are continued until the COIN symbol is rearranged. However, the second embodiment is not limited thereto. For example, the free games may be continuously executed when a predetermined number or more of predetermined symbols such as the BELL symbols are rearranged in the display window  56 , and the free games may be terminated when the predetermined number or more of predetermined symbols are not rearranged. In addition, even when the predetermined number or more of the predetermined symbols such as the BELL symbols are rearranged in the display window  56 , the free games may be terminated if the COIN symbol is rearranged. 
     Third Embodiment 
     Hereinbefore, the first and second embodiment are described. Hereinafter, a third embodiment will be described. It is to be noted that the description regarding parts of a configuration in common with those of the first and second embodiments is omitted and only parts of the configuration differing from those of the first and embodiments will be described with reference to the accompanying drawings. 
     &lt;Symbol Determination Table for Basic Game&gt; 
       FIG. 46  shows an example of a symbol determination table for a basic game in the third embodiment. In said table, arrangement of symbols on each of the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E and values of corresponding weights are different from those in the first embodiment. However, a basic function is the same as that of the symbol determination table for the basic game ( FIG. 10 ) in the first embodiment. 
     &lt;Payout Table&gt; 
       FIG. 47  shows an example of a payout table in the third embodiment. In said tables, kinds of symbols are partly different from those in the first embodiment. However, a basic function is the same as that of the payout table ( FIG. 11 ) in the first embodiment. 
     &lt;Game State Transition&gt; 
       FIG. 48  is a diagram showing a pattern of state transition in a gaming machine  10  in the third embodiment. 
     The gaming machine  10  executes two kinds of games: a basic game and free games as a feature game. In the gaming machine  10 , the basic game is executed as a main game, and when in the basic game, a trigger (event) has occurred, the game shifts to the feature game. 
     In the third embodiment, a condition on which the trigger occurs is that in the display window  56  of the symbol display unit  40 , SEVEN symbols have been rearranged (three or more SEVEN symbols have been rearranged) on a predetermined condition. Of course, other condition may be set as the condition on which the trigger occurs. 
     As can be understood from  FIG. 48 , in the basic game, a unit game is repeated until the SEVEN symbols have been rearranged in the display window  56  of the symbol display unit  40  on the predetermined condition. In this basic game, when a combination of the symbols rearranged on a payline matches any winning combination shown in the payout table, coins whose number is in accordance with a payout for that combination are paid out. In addition, when in the display window  56 , the predetermined number or more of the predetermined winning symbols have been rearranged, coins whose number is in accordance with a payout associated with the number of the rearranged winning symbols are paid out. 
     In the free games, a unit game similar to the unit game in the basic game is repeatedly executed without consuming any gaming media such as medals. When the number of remaining free games becomes “0” (that is, a value on the number-of-free-game counter  324  is zero), the game is terminated and the game reverts to the basic game. 
     In the third embodiment, the number of free games upon starting the free games is set to 5. 
     &lt;Feature Game Processing&gt; 
     Next, with reference to  FIG. 49 , feature game processing will be described.  FIG. 49  is a flowchart of the feature game processing in the gaming machine  10  according to the third embodiment of the present invention. 
     This processing is invoked in a case where it is determined that a feature game trigger is established in the main control processing shown in  FIG. 13 . First, the effect control processing part  312  operatively executed by the main CPU  222  conducts control to display an effect video image on the video display unit  110  in order to conduct effects related to the start of a feature game (step S 251 ). 
     Next, the game counter processing part  306  operatively executed by the main CPU  222  sets the number of free games as five to the value stored in the number-of-free-game storage region (the number-of-free-game counter  324 ) (step S 252 ). Subsequently, the game mode determination processing part  316  operatively executed by the main CPU  222  sets the game mode to the free game mode, and as described later, a unit game which is similar to that in the basic game is repeatedly conducted at five times. 
     Next, the main CPU  222  conducts symbol lottery processing for the free games, later described with reference to  FIG. 50  (step S 253 ). In this processing, to-be-stopped symbols are determined based on the later-described first and second symbol determination tables for the free games and random number values for the determination of symbols. 
     Next, the effect control processing part  312  operatively executed by the main CPU  222  conducts content-of-effect determination executing processing (step S 254 ). The main CPU  222  extracts effect random number values, determines any of a plurality of the predetermined contents of effects by conducting a lottery, and executes the contents of effects at the timing of the determined contents of effects. For example, an effect video image is displayed on the video display unit  110 , audio (such as background music (BGM)) is outputted by the speaker  112 , the lamp  114  is lit, and effect processing is applied to these elements, etc., whereby control of a display mode or the like is conducted. 
     Next, the main CPU  222  conducts symbol display control processing which is similar to that in the main control processing shown in  FIG. 16  (step S 255 ). It is to be noted that the symbol display control processing at step S 255  can be conducted prior to or in parallel with the execution of the contents of effects at step S 254 . Next, the main CPU  222  conducts number-of-payout determination processing which is similar to that in the main control processing shown in  FIG. 16  (step S 256 ). 
     Subsequently, the game counter processing part  306  operatively executed by the main CPU  222  subtracts “1” from a value on the number-of-free-game counter  324  in response to the termination of one free game (step S 257 ). The main CPU  222  determines whether or not the number-of-free-game counter  324  is set to 0 (step S 258 ). When the value on the number-of-free-game counter  324  is not set to 0, the main CPU  222  shifts the processing to step S 253  in order to conduct a new free game. When the number-of-free-game counter  324  is set to 0, the main CPU  222  finishes the feature game processing. 
     &lt;Symbol Lottery Processing for Free Games&gt; 
     Next, with reference to  FIG. 50 , symbol lottery processing for the free games will be described.  FIG. 50  is a flowchart of the symbol lottery processing for the free games in the gaming machine  10  according to the third embodiment of the present invention. 
     First, with reference to a symbol determination table selection table ( FIG. 51 ), the main CPU  222  selects one symbol determination table from the first and second symbol determination tables for the free games (step S 271 ). 
     According to the symbol determination table selection table shown in  FIG. 51 , one symbol determination table is selected from the first and second symbol determination tables for the free games. 
     Here, in the first symbol determination table for the free games ( FIG. 52 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 1” or “No. 5” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the SEVEN symbols are invariably rearranged on the “No. 1” or “No. 5” payline. Therefore, a ready-to-win combination of the SEVEN symbols is invariably established. 
     In the second symbol determination table for the free games ( FIG. 53 ), appearance probabilities of the respective symbols are set such that the SEVEN symbols are easily rearranged on the “No. 1” or “No. 4” payline. Further, the appearance probabilities of the respective symbols are set such that when the first reel  52 A and the second reel  52 B are stopped, the SEVEN symbols are invariably rearranged on the “No. 1” or “No. 4” payline. Therefore, a ready-to-win combination of the SEVEN symbols is invariably established. 
     As described above regarding the first and second symbol determination tables for the free games in the third embodiment, a payline on which the SEVEN symbols are rearranged as the winning combination can be varied each time each of the free games is played. Thus, diversity can be imparted to patterns, in each of which the SEVEN winning combination is established. In addition, a payline on which the ready-to-win combination is established can be varied each time each of the free games is played. Thus, diversity can be imparted to patterns, in each of which the ready-to-win combination for the BELL or SEVEN winning combination is displayed. In addition, since the ready-to-win combination for the SEVEN winning combination is invariably established, a player can play the games while having a sense of expectation that the SEVEN winning combination could be established. 
     Next, the random number generation processing part  302  operatively executed by main CPU  222  extracts random number values for the determination of symbols (step S 272 ). The symbol determination processing part  304  operatively executed by the main CPU  222  determines to-be-stopped symbols of each of the reels by conducting a lottery based on the random number values extracted at step S 272  (step S 273 ). The main CPU  222  conducts the lottery with respect to each of the reels (the first to fifth reels  52 A,  52 B,  52 C,  52 D, and  52 E) and determines any of 22 symbols (code numbers “00” to “21”) as the to-be-stopped symbols based on one symbol determination table selected at step S 271  from the first and second symbol determination tables for the free games ( FIG. 52  and  FIG. 53 ). At this time, appearance probabilities of the 22 symbols (code numbers “00” to “21”) are defined in accordance with the weights in the symbol determination table. 
     Next, the main CPU  222  stores the to-be-stopped symbols of each of the reels in a symbol storage region provided in the RAM  226  (step S 274 ). Next, with reference to the payout table ( FIG. 47 ), the winning determination processing part  310  operatively executed by the main CPU  222  determines a winning combination based on the combination of symbols stored in the symbol storage region (step S 275 ). The main CPU  222  determines whether or not a combination of symbols on a payline displayed by each of the reels matches any combination of symbols defined in the payout table or whether or not a predetermined number or more of predetermined winning symbols defined in the payout table are rearranged in the display window  56 , thereby determining a winning combination. 
     &lt;Effects in Free Games&gt; 
       FIGS. 54A to 54C  are diagrams illustrating effects executed when the feature game trigger is determined as being established in the third embodiment. In the effects, it is indicated that the number of free games as the feature game is five. In  FIGS. 54A to 54C , display regions  61  to  65  are provided in an upper part of the display panel  58  provided on the periphery of the display window  56 . Five LEDs which are operable to emit light from an inside of the slot machine  10  are provided so as to be associated with these five display regions. In addition, on a front face of the display region  61 , a transparent sheet having “1” depicted thereon is provided. Similarly, on respective front faces of the display region  62 , the display region  63 , the display region  64 , and the display region  65 , transparent sheets having “2”, “3”, “4”, and “5” depicted thereon respectively are provided. In addition, a color of each of the LEDs associated with the display regions  61  to  65  can be arbitrarily set. For example, blue is set for the display region  61 ; red is set for the display region  62 ; green is set for the display region  63 , blue is set for the display region  64 ; and red is set for the display region  65 . 
     When the feature game trigger is determined as being established, first, the LED associated with the display region  61  emits blue light and the display region  61  is lit up, thereby allowing the numeric character “1” to be visible ( FIG. 54A ). Next, the LED associated with the display region  62  emits red light and the display region  62  is lit up, thereby allowing the numeric character “2” to be visible ( FIG. 54B ). The same processing as mentioned above is executed sequentially for the display regions  63  to  65 , and lastly, the LED associated with the display region  65  emits red light and the display region  65  is lit up, thereby allowing the numeric character “5” to be visible ( FIG. 54C ). As described above, the display regions  61  to  65  are sequentially lit up, thereby allowing a player to recognize that the number of free games at the time point when the feature game trigger is established is five. 
       FIGS. 55A to 55C  are diagrams illustrating effects conducted when the free games are executed in the third embodiment. In the effects, the number of remaining free games is notified. First, when the number of remaining free games is five, all of the display regions  61  to  65  are lit up ( FIG. 55A ). Thereafter, when one game has already been played, the LED associated with the display region  65  is lit off, thereby notifying that the number of remaining games is four ( FIG. 55B ). In accordance with the number of free games which have already been played, the LEDs associated with the display regions  64 ,  63 ,  62 , and  61  are sequentially lit off and lastly, all of the LEDs associated with the display regions  61  to  65  are lit off, thereby notifying that the number of free games is zero. 
     In the third embodiment, although the number of free games which is set immediately after shifting to the free games is set to 5, the number thereof is not limited thereto and may be less than 5 or exceed 5. 
     REFERENCE SIGNS LIST 
     
         
         
           
               52 A,  52 B,  52 C,  52 D,  52 E reel 
               222  main CPU 
               224  ROM 
               226  RAM