Patent Publication Number: US-2009227358-A1

Title: Slot Machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of U.S. Provisional Application No. 61/034,690 filed on Mar. 7, 2008. The contents of this application are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a slot machine. 
     2. Description of the Related Art 
     Conventionally, slot machines known as a type of gaming machines are constituted so as to: start games by players inserting coins or the like into the gaming machine; variably display columns of symbols in predetermined regions of the gaming machine while they are displayed in a stopped state after a predetermined period has elapsed; and award payout based on a combination of symbols in a stopped state. 
     In addition, the above slot machines are generally constituted to judge whether or not a winning combination allowed to award payout is established, based on whether or not a predetermined number of symbols of the same type (for example, “CHERRY” or “7”) are arranged along a preset payline. In the conventional slot machine, in a case where a predetermined number or more of symbols of the same type are arranged, it has been a common routine to award payout based on the number of the aforementioned arranged symbols, regardless of the payout line. 
     Further, many of the conventional slot machines have been known which conduct two types of games, i.e., a basic game and a free game. The basic game is executed upon consumption of gaming values (such as coins or credits) corresponding to the amount of bet. On the other hand, the free game is executed without consuming gaming values corresponding to the amount of bet. 
     The basic game is switched to the free game when a predetermined condition is met. The condition includes a case in which, for example, a specific symbol is displayed in a stopped state during the basic game. The free game is switched to the basic game when a predetermined condition is met. The condition includes a case in which, for example, the free games are executed a predetermined number of times. 
     In the conventional slot machines, it has been a common routine to raise players&#39; feeling of expectation for the free game by changing arrangement of symbols during the free game differently from that during the basic game. For example, U.S. Pat. No. 6,394,902-B1 describes a slot machine in which a total of fifteen symbols are displayed in three rows and five columns with the use of video reels. This conventional slot machine changes symbol columns arranged on reels during the free game differently from that during the basic game, in which eight types of symbols are decreased to five. In this manner, a probability of awarding payout can be apparently increased during the free game. 
     In the aforementioned conventional slot machines, however, irrespective of whichever of the basic game and the free game is in progress, the symbols of different types have been randomly arranged in combination and sequential order. These slot machines determine the contents of the prize to be awarded, based on a combination of multiple symbols that have been arranged in a display device. Therefore, players are allowed to have the feeling of expectation only for random payout based on a combination of plural types of symbols that have been randomly arranged in the display device. Accordingly, a need exists for the advent of a slot machine which can offer new entertainability. 
     The present invention has been made in view of the above-described circumstance. It is an object of the present invention to provide a novel slot machine by enhancing entertainability associated with arrangement of the symbols. 
     SUMMARY OF THE INVENTION 
     A first aspect of the present invention is a slot machine including: a display device for displaying a symbol matrix display region having a first display region and a second display region; an input device for accepting an input of a normal BET and that of a side-BET different from the normal BET; a memory for storing plural types of symbol image data; and a controller for controlling the display device and the input device, the controller being programmed to: (a) execute a basic game; (b) read, from among the symbol image data stored in the memory, at least two symbol image data including symbol image data that may be combined with each other on condition that the side-BET is input, during the basic game, reduce a horizontal or vertical direction of the read symbol image data so that said at least two symbol images are displayed in a region for displaying a single symbol, generate, based on the reduced symbol image data, combined symbol image data for displaying a combined symbol to be displayed in the first display region; (c) rearrange the combined symbol combined corresponding to the combined symbol image data in the first display region within the symbol display region and rearrange symbols corresponding to the plural types of symbol image data in the second display region within the symbol display region, during the basic game; (d) generate the combined symbol image data obtained by changing scaling ratios of the symbol image data so that area ratios of respective symbol images of the combined symbol are changed according to the number of times in executing the basic games, and rearrange the combined symbol in the first display region according to the changed combined symbol image data; and (e) selectively execute one bonus game from among a plurality of bonus games according to types of the combination, in a case where a combination of the combined symbol displayed in the first display region and single symbols displayed in the second display region matches a predetermined combination. 
     According to the first aspect of the present invention, the area ratios of the respective symbol images of the combined symbol change according to the number of times in executing the basic games and according to the combination of the changed combined symbol and the single symbols, the bones game is executed. Thus, a bonus game with a high level of expectation can be realized according to the combination of the combined symbol and the single symbols. This enhances the entertainability associated with rearrangement of the symbols. 
     A second aspect of the present invention is a slot machine constituted as set forth below. In the first aspect, the controller, in the itemized (d), gradually changes the area ratios of the respective symbol images of the combined symbol according to the number of times in executing the basic games to transform the combined symbol into the single symbols, thereby rearranging the single symbols based on the combined symbol in the first display region, and the controller, in the itemized (e), selectively executes one bonus game from among a plurality of bonus games according to types of the combination, in a case where a combination of the single symbols transformed from the combined symbol displayed in the first display region and the single symbols displayed in the second display region matches a predetermined combination. 
     According to the second aspect of the present invention, the area ratios of the respective symbol images of the combined symbol gradually change according to the number of times in executing the basic games to transform the combined symbol into single symbols, thereby executing the bonus game according to the combination of the combined symbol and the single symbols transformed from the combined symbol. Thus, a bonus game with a high level of expectation can be realized according to the combination of the combined symbol and the single symbols transformed from the combined symbol. This enhances the entertainability associated with rearrangement of the symbols. 
     A third aspect of the present invention is a slot machine constituted as set forth below. In the first aspect, a memory for cumulatively storing a progressive value is further included, in which the controller, in the itemized (b), reads the symbol image data from the memory with referring to the progressive value of the memory so that one jackpot symbol from among the plurality of jackpot symbols is added to the combined symbol in response to a jackpot becoming a predetermined progressive value. 
     According to the third aspect of the present invention, when a predetermined progressive value is obtained, the jackpot symbol is added to the combined symbol, the area ratios of the respective symbol images of the combined symbol gradually change according to the number of times in executing the basic games to transform the combined symbol into the single symbols. Then, according to the combination of the combined symbol and the single symbols transformed from the combined symbol, the jackpot bonus game is executed. Thus, a bonus game with a high level of expectation can be realized according to the combination of the combined symbol and the single symbols transformed from the combined symbol. This enhances the entertainability associated with rearrangement of the symbols. 
     A fourth aspect of the present invention is a slot machine including: a display device for displaying a symbol matrix display region having a first display region and a second display region; an input device for accepting an input of a normal BET and that of a side-BET different from the normal BET; a memory for storing plural types of symbol image data; and a controller for controlling the display device and the input device, the controller being programmed to: (a) execute a basic game; (b) read, from among the symbol image data stored in the memory, at least two symbol image data including symbol image data that may be combined with each other on condition that the side-BET is input, during the basic game, reduce a horizontal direction or a vertical direction of the read symbol image data so that said at least two symbol images are displayed in a region for displaying a single symbol, generate, based on the reduced symbol image data, combined symbol image data for displaying a combined symbol to be displayed in the first display region; (c) rearrange the combined symbol combined corresponding to the combined symbol image data in the first display region within the symbol display region and rearrange symbols corresponding to the plural types of symbol image data in the second display region within the symbol display region, during the basic game; (d) gradually change area ratios of respective symbol images of the combined symbol according to the number of times in executing the basic games to transform the combined symbol into the single symbols, thereby rearranging the single symbols based on the combined symbol in the first display region, and (e) selectively execute one bonus game from among a plurality of bonus games according to types of the combination, in a case where a combination of the single symbols transformed from the combined symbol displayed in the first display region and the single symbols displayed in the second display region matches a predetermined combination. 
     According to the fourth aspect of the present invention, the area ratios of the respective symbol images of the combined symbol gradually change according to the number of times in executing the basic games to transform the combined symbol into the single symbols. Then, according to the combination of the symbols, the bonus game is executed. Thus, a bonus game with a high level of expectation can be realized according to the combination of the combined symbol and the single symbols transformed from the combined symbol. This enhances the entertainability associated with rearrangement of the symbols. 
     A fifth aspect of the present invention is a slot machine constituted as set forth below. In the fourth aspect, a memory for cumulatively storing a progressive value is further included, in which the controller, in the itemized (b), reads the symbol image data from the memory with referring to the progressive value of the memory so that one jackpot symbol from among the plurality of jackpot symbols is added to the combined symbol in response to a jackpot becoming a predetermined progressive value. 
     According to the fifth aspect of the present invention, upon becoming a predetermined progressive value, the jackpot symbol is added to the combined symbol, the area ratios of the respective symbol images of the combined symbol gradually change according to the number of times in executing the basic games to transform the combined symbol into the single symbols. Then, according to the combination of the combined symbol and the single symbols transformed from the combined symbol, the jackpot bonus game is executed. Thus, a bonus game with a high level of expectation can be realized according to the combination of the combined symbol and the single symbols transformed from the combined symbol. This enhances the entertainability associated with rearrangement of the symbols. 
     A sixth aspect of the present invention is a slot machine including: a display device for displaying a symbol matrix display region having a first display region and a second display region; an input device for accepting an input of a normal BET and that of a side-BET different from the normal BET; a memory for storing plural types of symbol image data and cumulatively storing a progressive value; a controller for controlling the display device and the input device, the controller being programmed to: (a) execute a basic game; (b) read the symbol image data from the memory with referring to the progressive value of the memory so that one jackpot symbol from among the plurality of jackpot symbols is added in response to a jackpot becoming a predetermined progressive value, out of at least two symbol image data including the symbol image data that may be combined on condition that the side-BET is input, from among the symbol image data stored in the memory, during the basic game, reduce a horizontal direction or a vertical direction of the read symbol image data so that said at least two symbol images are displayed in a region for displaying a single symbol, generate, based on the reduced symbol image data, combined symbol image data for displaying a combined symbol to be displayed in the first display region; (c) rearrange the combined symbol combined corresponding to the combined symbol image data in the first display region within the symbol display region and rearrange symbols corresponding to the plural types of symbol image data in the second display region within the symbol display region, during the basic game; (d) gradually change area ratios of respective symbol images of the combined symbol according to the number of times in executing the basic games to transform the combined symbol into the single symbols, thereby rearranging the single symbols based on the combined symbol in the first display region, and (e) selectively execute one bonus game from among a plurality of bonus games according to types of the combination, in a case where a combination of the single symbols transformed from the combined symbol displayed in the first display region and the single symbols displayed in the second display region matches a predetermined combination. 
     According to the sixth aspect of the present invention, upon becoming a predetermined progressive value, the jackpot symbol is added to the combined symbol, the area ratios of the respective symbol images of the combined symbol gradually change according to the number of times in executing the basic games to transform the combined symbol into the single symbols. Then, according to the combination of the combined symbol and the single symbols transformed from the combined symbol, the jackpot bonus game is executed. Thus, a bonus game with a high level of expectation can be realized according to the combination of the combined symbol and the single symbols transformed from the combined symbol. This enhances the entertainability associated with rearrangement of the symbols. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a view showing an exemplary symbol matrix during a basic game according to a first embodiment; 
         FIG. 1B  is a view showing an exemplary symbol matrix during the basic game according to the first embodiment; 
         FIG. 1C  is a view showing an exemplary symbol matrix during the basic game according to the first embodiment; 
         FIG. 2  is a perspective view schematically showing a frame format of a slot machine according to the first embodiment; 
         FIG. 3  is a block diagram depicting an internal construction of the slot machine shown in  FIG. 2 ; 
         FIG. 4A  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  according to the first embodiment during the basic game; 
         FIG. 4B  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the basic game; 
         FIG. 5A  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the basic game according to the first embodiment; 
         FIG. 5B  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the basic game according to the first embodiment; 
         FIG. 6A  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during a free game according to the first embodiment; 
         FIG. 6B  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the free game according to the first embodiment; 
         FIG. 6C  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the free game according to the first embodiment; 
         FIG. 7A  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during a jackpot bonus game according to the first embodiment; 
         FIG. 7B  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the jackpot bonus game according to the first embodiment; 
         FIG. 8A  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the jackpot bonus game according to the first embodiment; 
         FIG. 8B  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the jackpot bonus game according to the first embodiment; 
         FIG. 9A  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the jackpot bonus game according to the first embodiment; 
         FIG. 9B  is a view showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the jackpot bonus game according to the first embodiment; 
         FIG. 10  is a flowchart showing a subroutine of a main process; 
         FIG. 11  is a flowchart showing a subroutine of a game execution process according to the first embodiment; 
         FIG. 12  is a flowchart showing a subroutine of a basic game symbol rearrangement process according to the first embodiment; 
         FIG. 13  is a flowchart showing a subroutine of a symbol combining process according to the first embodiment; 
         FIG. 14  is a flowchart showing a subroutine of a free-game execution process according to the first embodiment; 
         FIG. 15  is a flowchart showing a subroutine of a jackpot bonus game execution process according to the first embodiment; 
         FIG. 16  is a view schematically depicting a frame format of an appearance of a slot machine according to a second embodiment; 
         FIG. 17A  is a view showing an exemplary symbol matrix during a basic game according to the second embodiment; 
         FIG. 17B  is a view showing an exemplary symbol matrix during the basic game according to the second embodiment; and 
         FIG. 17C  is a view showing an exemplary symbol matrix during the basic game according to the second embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First, a slot machine  10  according to a first embodiment will be described in detail with referring to the drawings. The slot machine according to the below-described first embodiment is a so-called video slot machine, which has an image display panel such as a liquid crystal display and executes a game by displaying images of various symbols on the image display panel. 
       FIGS. 1A ,  1 B, and  1 C are views each showing an exemplary symbol matrix during a basic game according to the first embodiment. The slot machine  10  according to the present invention executes any one of three modes of games, i.e., a basic game, a free game, and a progressive bonus game. The basic game is executed upon consuming a gaming value corresponding to the amount bet by a player. The free game is executed without consuming a gaming value. The progressive bonus game is executed when a predetermined progressive value is obtained. While the slot machine  10  is of a stand-alone type, which is not connected to a network, the present invention is also applicable to a networked slot machine. 
     As shown in  FIGS. 1A ,  1 B, and  1 C, elements of the symbol matrix SM are displayed on the lower image display panel  16  described later, included in the slot machine  10 . In the elements of the symbol matrix SM, a total of fifteen symbols in three rows and five columns are rearranged. 
     In the first embodiment of the present invention, any of symbols “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128” are rearranged in the elements of symbol matrix SM. A payout is determined based on the number of symbols of respective types rearranged in the elements of the symbol matrix SM. On condition that a side-BET is input, a jackpot symbol is added to a combined symbol  129 , and is rearranged. 
     As shown in  FIG. 1A , when the predetermined progressive value is obtained during the basic game, any of the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129” are rearranged in any of the elements of the symbol matrix SM in a first display region  70  of the symbol matrix SM. The “combined symbol 129” is a symbol image of which the horizontal or vertical direction is reduced so that at least two symbol images are displayed in an element of the symbol matrix SM, in which a single symbol is displayed. The two symbols are combined with each other on condition that the side-BET is input. In this case, since the side-BET is input, a combination formed of two “combined symbols 129” and one “sub character 122” is rearranged. In the “combined symbol 129”, the horizontal direction of the symbols of the main character  121  and the sub character  122  or jackpot symbol is reduced. In a second display region  71 , in any of the elements of the symbol matrix SM, the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128” are rearranged. 
     As shown in  FIG. 1B , in the “combined symbol 129” rearranged in the first display region  70  in  FIG. 1A , area ratios of the respective symbols of the combined symbol are changed according to the number of times in executing the basic games. In this case, according to the number of times in executing the basic games, a scaling ratio in a horizontal direction between the main character  121  and the sub character  122  or jackpot symbol is changed so that the symbol of the main character  121  added to the “combined symbol 129” is rearranged more widely or the symbol of the sub character  122  or jackpot symbol is rearranged more widely. In this way, the “combined symbol 129” is changed. 
     As shown in  FIG. 1C , after the area ratios of the respective symbols of the combined symbol are changed in  FIG. 1B , according to types of the combination of the changed “combined symbol 129” rearranged in the first display region  70  and a single symbol rearranged in the second display region  71 , one bonus game is selectively executed from among a plurality of bonus games. In this case, since a combination of three sub characters  122  is rearranged, the jackpot bonus game is selected and executed according to the types of the combination. 
       FIG. 2  is a view schematically depicting a frame format of an appearance of the slot machine according to the first embodiment of the present invention. The gaming media used in the slot machine  10  include coins, bills, or electronic value information equivalent thereto. In the present invention, however, the gaming media are not limitative thereto in particular, and can include medals, tokens, electric money, and tickets, for example. The above tickets are not limitative in particular, and can include barcode-attached tickets or the like, as described later, for example. 
     The slot machine  10  is provided with a cabinet  11 , a top box  12  installed on an upper side of the cabinet  11 , and a main door  13  provided on a front surface of the cabinet  11 . 
     The lower image display panel  16  serving as a display device is provided in front of the main door  13 . The lower image display panel  16  is provided with a liquid crystal panel, which displays the fifteen elements of the symbol matrix SM in three rows and five columns. A single symbol is arranged in each of the elements of the symbol matrix SM. 
     A credit amount display section  31  of the lower image display panel  16  displays the number of coins credited by way of an image. A payout amount display unit  32  displays by way of an image the number of, for example, coins to be paid if a predetermined number or more symbols of respective types are rearranged in the elements of the symbol matrix SM  28 . 
     Provided on a lower side of the lower image display panel  16  are a control panel  20  having a plurality of buttons  23  to  27  through which command regarding the process of the game will be input by a player, a coin receiving slot  21  for receiving coins into the cabinet  11 , and a bill validator  22 . 
     On the control panel  20 , a start button  23 , a change button  24 , a cashout button  25 , a 1-BET button  26 , and a MAX-BET button  27  are provided. The start button  23  is intended for entering a command for starting the game. The change button  24  is intended for use in asking an attendant of the gaming facility for change. The cashout button  25  is intended for entering a command for paying out the credited coins to a coin tray  18  through a coin payout exit  19 . 
     The 1-BET button  26  is intended for entering a command for betting one coin among the credited coins on the game. The MAX-BET button  27  is intended for entering a command for betting the upper number (50 in this embodiment) of coins that can be bet per game among the credited coins on the game. 
     The bill validator  22  validates whether or not a bill is legitimate and accepts a legitimate bill into the cabinet  11 . The bill validator  22  may be configured so that a barcode-attached ticket  39  described later is readable thereby. Provided on a lower front surface of the main door  13 , that is, at a lower part of the control panel  20 , is a berry glass  34  on which characters of the slot machine  10  and the like are depicted. 
     On a front surface of the top box  12 , an upper image display panel  33  is provided. The upper image display panel  33  has a liquid crystal panel, which displays images for introducing the game contents or explaining game rules, for example. 
     Also, on the top box  12 , a speaker  29  and a lamp  30  are provided. On a lower side of the upper image display panel  33 , a ticket printer  35 , a card reader  36 , a data display unit  37 , and a key pad  38  are provided. The ticket printer  35  prints on the ticket, a barcode having encoded thereon data such as the credit amount, the date and time, and the identification number of the slot machine  10 , and outputs the printed ticket as the barcode-attached ticket  39 . The player can play the game on another slot machine with the barcode attached ticket  39  by causing this slot machine to read the barcode attached ticket  39 . Alternatively, the player can exchange the barcode-attached ticket  39  with the bills or the like at a predetermined place (at a cashier inside a casino, for example) of the gaming facility. 
     The card reader  36  reads data from and write data into a smart card. The smart card is to be owned by the player, which stores data for identifying the player or data regarding the log of games executed by the player, for example. The smart card may store data corresponding to coins, bills, or a credit. As an alternative of a smart card, a magnetic stripe card may be employed. The data display  37  is made up of a fluorescent display and the like, and displays the data read by the card reader  36  or the data input by the player through the key pad  38 , for example. The key pad  38  inputs data and commands regarding the ticket issuance or the like. 
       FIG. 3  is a block diagram depicting an internal construction of the slot machine shown in  FIG. 2 . A gaming board  50  includes: a CPU (Central Processing Unit)  51 , a ROM (Read Only Memory)  55  and a boot ROM  52  interconnected by an internal bus; a card slot  53 S corresponding to a memory card  53 ; and an IC socket  54 S corresponding to a GAL (Generic Array Logic)  54 . 
     The memory card  53  is formed of a nonvolatile memory such as Compact Flash (registered trademark) and stores game programs. The game programs include a symbol selection program. The aforementioned symbol selection program is intended for determining the symbols to be rearranged in the elements of the symbol matrix SM  28 . The aforementioned symbol selection program includes symbol weighing data respectively corresponding to plural types of payout ratios (80%, 84%, and 88%, for example). The symbol weighing data is indicative of the correspondence relationship between the respective symbols and one or more random numeric values which come under a predetermined numerical range (0 to 255). The payout ratio is determined according to the payout-ratio setting data output from the GAL  54 . The symbols to be rearranged in the elements of the symbol matrix SM  28  are determined depending upon the symbol weighing data corresponding to the payout ratio. Further, the game programs include table data indicating the correspondence relationship between each of the symbols and a payout. 
     Also, the card slot  53 S is configured to allow the memory card  53  to be inserted thereinto or ejected therefrom, and is connected to a mother board  40  through an IDE pass. Accordingly, the memory card  53  can be ejected from the card slot  53 S, other game programs and other game system programs can then be written into the memory card  53 , and further, the memory card  53  can be inserted into the card slot  53 S, thereby allowing the player to change the types and contents of games executed in the slot machine  10 . The game program includes programs concerning a game progress. Furthermore, the game program includes image data or sound data to be output during the game. The image data include, for example, image data indicative of the symbol matrix. 
     The GAL  54  is a type of a PLD having a fixed OR array structure. The GAL  54  includes plural input ports and plural output ports. Where predetermined data is input to the input port, the GAL  54  outputs data corresponding to the aforementioned data from the output port. The data output from this output port is equivalent to the aforementioned payout-ratio setting data. Further, the IC socket  54 S is configured to allow the GAL  54  to be attached thereto and detached therefrom, and is connected to the mother board  40  by a PCI bus. Accordingly, the GAL can be replaced with the replacement GAL  54  to change the payout-ratio setting data. 
     The CPU  51 , the ROM  55 , and the boot ROM  52  interconnected by the internal bus are connected to the mother board  40  by the PCI bus. The PCI bus serves to transmit signals between the mother board  40  and the gaming board  50  and supply power from the mother board  40  to the gaming board  50 . 
     The mother board  40  is constructed using a general-purpose mother board commercially available (a printed circuit board on which essential parts of a personal computer are mounted) and includes: a main CPU (Central Processing Unit)  41 , a ROM (Read Only Memory)  42 ; a RAM (Random Access Memory)  43 ; and a communication interface  44 . The main CPU  41  functions as a processor for controlling a display device and a memory according to the embodiment of the present invention. 
     The ROM  42  is made up of a memory device such as a flash memory and stores thereon a program such as BIOS (Basic Input/Output System) executed by the main CPU  41 , and permanent data. When the BIOS is executed by the main CPU  41 , processing of initializing predetermined peripheral devices is carried out and processing of capturing game programs and game system programs stored in the memory card  53  through the gaming board  50  is started. In the present invention, the contents of the ROM  42  may be rewritable or not. 
     The RAM  43  stores data and a program used when the main CPU  41  is activated. The RAM  43  can also store game programs. The RAM  43  further stores data concerning the credit amount, the number of coin-in or coin-out for one game, and the like. 
     Both a main body PCB (Printed Circuit Board)  60  and a door PCB  80 , which will be described later, are connected to the mother board  40  by USB. A power supply unit  45  is also connected to the mother board  40 . 
     Connected to the main body PCB  60  and the door PCB  80  are: equipment and devices which generate input signals to be input to the main CPU  41 ; and equipment and devices of which operations are controlled by a control signal output from the main CPU  41 . The main CPU  41  executes a game program stored in the RAM  43  based on an input signal having been input to the main CPU  41  and performs a predetermined computational process, thereby storing results thereof in the RAM  43  or transmitting a control signal to each of equipment and devices as a control process therefore. 
     A lamp  30 , a hopper  66 , a coin detecting section  67 , a graphic board  68 , a speaker  29 , a touch panel  69 , the bill validator  22 , the ticket printer  35 , the card reader  36 , a key switch  38 S, and the data display unit  37  are connected to the main body PCB  60 . The lamp  30  is lit up in a predetermined pattern based on a control signal output from the main CPU  41 . 
     The hopper  66  is installed in the cabinet  11  and pays out a predetermined number of coins from the coin payout exit  19  to the coin tray  18  based on a control signal output from the main CPU  41 . The coin detecting section  67  is installed inside the coin payout exit  19  and outputs an input signal to the main CPU  41  upon detecting that a predetermined number of coins have been paid out from the coin payout exit  19 . 
     The graphic board  68  controls, based on a control signal output from the main CPU  41 , images to be displayed on the upper image display panel  33  and the lower image display panel  16 . The credit amount stored in the RAM  43  is displayed on the credit amount display section  31  (see  FIG. 2 ) of the lower image display panel  16 . The number of coins to be paid out is displayed at the payout amount display section  32  (see  FIG. 2 ) of the lower image display panel  16 . The graphic board  68  is equipped with a VDP (Video Display Processor) which generates image data based on a control signal output from the main CPU  41  and a video RAM which temporarily stores image data generated by the VDP, and the like. The image data used in generating the image data with VDP is contained in the game program read from the memory card  53  and stored in the RAM  43 . 
     The bill validator  22  validates whether or not a bill is legitimate and accepts a legitimate bill into the cabinet  11 . Upon accepting a legitimate bill, the bill validator  22  outputs an input signal to the main CPU  41  based on the amount of the bill. The main CPU  41  stores in the RAM  43  the credit amount corresponding to the amount of bills transmitted by the input signal. 
     Based on a control signal output from the main CPU  41 , the ticket printer  35  prints on a ticket a barcode having encoded thereon data such as the credit amount, data and time, and the identification number of the slot machine  10  stored in the RAM  43 . Further, this printer outputs the printed ticket as the barcode-attached ticket  39 . The card reader  36  transmits to the main CPU  41  the data read from the smart card and writes the read data onto the smart card, based on a control signal from the main CPU  41 . The key switch  38 S is provided on the key pad  38 , and outputs a predetermined input signal to the main CPU  41  when the player operates the key pad  38 . The data display  37 , based on a control signal output from the main CPU  41 , displays the data read by the card reader  36  and the data input by the player through the key pad  38 . 
     The control panel  20 , a reverter  21 S, a coin counter  21 C, and a cold cathode tube  81  are connected to the door PCB  80 . The control panel  20  is provided with: a start switch  23 S corresponding to the start button  23 ; a change switch  24 S corresponding to the change button  24 ; a cashout switch  25 S corresponding to a cashout button  25 ; and a 1-BET switch  26 S corresponding to the 1-BET button  26 ; a MAX-BET switch  27 S corresponding to the MAX-BET button  27 . When the player operates the buttons  23  to  27 , the corresponding switches  23 S to  27 S output input-signals to the main CPU  41 , respectively. 
     The coin counter  21 C is provided inside the coin receiving slot  21 , and validates whether or not a legitimate coin is inserted by the player into the coin receiving slot  21 . Those other than the legitimate coins are discharged from the coin payout exit  19 . The coin counter  21 C outputs an input signal to the main CPU  41  when a legitimate coin is detected. 
     The reverter  21 S operates based on a control signal output from the main CPU  41  and distributes coins recognized as being legitimate by the coin counter  21 C into a cash box (not shown in the drawings) or the hopper  66  which is arranged in the slot machine  10 . In other words, when the hopper  66  is filled with coins, legitimate coins are distributed by the reverter  21 S into the cash box. On the other hand, when the hopper  66  is not filled with coins, legitimate coins are distributed into the hopper  66 . The cold cathode tube  81  functions as a backlight installed on a rear face side of each of the lower image display panel  16  and the upper image display panel  33 , and is lit up based on a control signal output from the main CPU  41 . 
       FIGS. 4A to 9B  are diagrams illustrating an exemplary image displayed on the slot machine illustrated in  FIG. 2  according to the first embodiment.  FIGS. 4A and 4B  are diagram illustrating an exemplary symbol matrix displayed on the slot machine illustrated in  FIG. 2  during the basic game according to the first embodiment. 
     As shown in  FIG. 4A , the lower image display panel  16  is made up of a display region  92 , an information display section  93 , an effect image display section  94 , and the like. The elements of the symbol matrix SM are displayed in the display region  92 . The information display section  93  is arranged upwardly of the display region  92  and is made up of a credit amount display section  93   a,  a BET amount display section  93   b,  a character information display section  93   c,  a PAID amount display section  93   d,  and a charge display section  93   e.    
     The number of coins currently credited is displayed at the credit amount display section  93   a  while the number of coins bet on one game is displayed at the BET amount display section  93   b.  The character information indicative of a current status of the game is displayed at the character information display section  93   c.  The characters of “PLAYNOW” are displayed during the play of the game, whereas the characters of “GAMEOVER” are displayed during the intervals between the plays of the game. The number of coins that have been successfully obtained in one game is displayed at the PAID amount display section  93   d,  whereas a conversion value of the credit amount based on a predetermined charge is displayed at the charge display section  93   e.    
     The effect image display section  94  displays effect images according to a type of the present slot game. In other words, the effect image display section  94  displays different effect images between the basic and free games. 
     Any of symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129” are rearranged in the elements of the symbol matrix SM on the lower image display panel  16 . 
     As shown in  FIG. 4A , when the predetermined progressive value is obtained during the basic game, in the first display region  70  of the symbol matrix SM, the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129” are rearranged in any of the elements of the symbol matrix SM. The “combined symbol 129” is a symbol image of which the horizontal or vertical direction is reduced so that at least two symbol images are displayed in an element of the symbol matrix SM, in which a single symbol is displayed. The two symbol images are combined on condition that the side-BET is input. In this case, since the side-BET is input, a combination formed of two “combined symbols 129” and one “sub character 122” is rearranged. In the “combined symbol 129”, the horizontal direction of the symbols of the main character  121  and the sub character  122  or jackpot symbol is reduced. In the second display region  71 , the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128” are rearranged in any of the elements of the symbol matrix SM. 
     As shown in  FIG. 4B , in the “combined symbol 129” rearranged in the first display region  70  in  FIG. 4A , area ratios of the respective symbols of the combined symbol are changed according to the number of times in executing the basic games. In this case, according to the number of times in executing the basic games, a scaling ratio in a horizontal direction between the main character  121  and the sub character  122  or jackpot symbol is changed so that the symbol of the main character  121  added to the “combined symbol 129” is rearranged more widely or the symbol of the sub character  122  or jackpot symbol is rearranged more widely. In this way, the “combined symbol 129” is changed. Thereafter, according to types of the combination of the changed “combined symbol 129” rearranged in the first display region  70  and the single symbol rearranged in the second display region  71 , one bonus game is to be selectively executed from among a plurality of bonus games. In this case, since a combination of three main characters  121  is rearranged, the free game is selected and executed according to the types of the combination. 
       FIGS. 5A and 5B  are views each showing an exemplary image displayed in the slot machine shown in  FIG. 2  during the basic game according to the first embodiment. When a predetermined progressive value is obtained during the basic game, in the first display region  70  of the symbol matrix SM, the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129” are rearranged in any of the elements of the symbol matrix SM. The “combined symbol 129” is a symbol image of which the horizontal or vertical direction is reduced so that at least two symbol images are displayed in an element of the symbol matrix SM, in which a single symbol is displayed. The two symbol images are combined on condition that the side-BET is input. In this case, since the side-BET is input, a combination formed of two “combined symbols 129” and one “main character 121” is rearranged. In the “combined symbol 129”, the horizontal direction of the symbols of the main character  121  and the sub character  122  or jackpot symbol is reduced. In the second display region  71 , in any of the elements of the symbol matrix SM, the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128” are rearranged. 
     As shown in  FIG. 5B , in the “combined symbol 129” rearranged in the first display region  70  in  FIG. 5A , area ratios of the respective symbols of the combined symbol are changed according to the number of times in executing the basic games. In this case, according to the number of times in executing the basic games, a scaling ratio in a horizontal direction between the main character  121  and the sub character  122  or jackpot symbol is changed so that the symbol of the main character  121  added to the “combined symbol 129” is rearranged more widely or the symbol of the sub character  122  or jackpot symbol is rearranged more widely. In this way, the “combined symbol 129” is changed. Thereafter, according to types of the combination of the changed “combined symbols 129” rearranged in the first display region  70  and the single symbol rearranged in the second display region  71 , one bonus game is selectively executed from among a plurality of bonus games. In this case, since a combination of three sub characters  122  is rearranged, the jackpot bonus game is selected and executed according to the types of the combination. 
       FIGS. 6A and 6B  are diagrams each illustrating an exemplary image displayed in the slot machine  10  shown in  FIG. 2  during the free game according to the first embodiment. As shown in  FIG. 6A , when the symbols rearranged in the elements of the symbol matrix SM in  FIG. 4B  form a combination for executing the free game, the free game is started. Upon starting the free game, the upper image display panel  33  displays a free-game-number display image  90   a  indicative of the number of times in executing the free games. In this case, the upper image display panel  33  displays the free-game-number display image  90   a  of “10 FREE GAMES” indicating that the number of times in executing the free games is determined to be 10 times. 
     As shown in  FIG. 6B , upon becoming the predetermined progressive value during the free game, in the first display region  70  of the symbol matrix SM, the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129” are rearranged in any of the elements of the symbol matrix SM. The “combined symbol 129” is a symbol image of which the horizontal or vertical direction is reduced so that at least two symbol images are displayed in an element of the symbol matrix SM, in which a single symbol is displayed. The two symbol images are combined with each other on condition that the side-BET is input. In this case, since the side-BET is input during the basic game, a combination formed of two “combined symbols 129” and one “sub character 122” is rearranged. In the “combined symbol 129”, the horizontal direction of the symbols of the main character  121  and the sub character  122  or jackpot symbol is reduced. In the second display region  71 , the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128” are rearranged in any of the elements of the symbol matrix SM. 
     As shown in  FIG. 6C , in the “combined symbol 129” rearranged in the first display region  70  in  FIG. 5B , area ratios of the respective symbols of the combined symbol are changed according to the number of times in executing the basic games. In this case, according to the number of times in executing the basic games, a scaling ratio in a horizontal direction between the main character  121  and the sub character  122  or jackpot symbol is changed so that the symbol of the main character  121  added to the “combined symbol 129” is rearranged more widely or the symbol of the sub character  122  or jackpot symbol is rearranged more widely. In this way, the “combined symbol 129” is changed. Thereafter, according to types of the combination of the changed “combined symbols 129” rearranged in the first display region  70  and the single symbol rearranged in the second display region  71 , one bonus game is selectively executed from among a plurality of bonus games. In this case, since a combination of three sub characters  122  is rearranged, the jackpot bonus game is selected and executed according to the types of the combination. 
       FIG. 7A  to  FIG. 9B  are diagrams each illustrating an exemplary image displayed in the slot machine  10  according to the first embodiment shown in  FIG. 2  during the jackpot bonus game. As shown in  FIG. 7A , when the symbols rearranged in the elements of the symbol matrix SM in  FIGS. 5B and 6C  form a combination for executing the jackpot bonus game, the jackpot bonus game is started. Upon judging the start of the jackpot bonus game, the upper image display panel  33  displays a jackpot bonus game display image  90   b  indicative of the start of the jackpot bonus game. In this case, the upper image display panel  33  displays the jackpot bonus game display image  90   b  which is “BONUS GAME” indicative of the fact that the jackpot bonus game has been started. 
     As shown in  FIG. 7B , upon starting the jackpot bonus game, the display region  92  displays a selection screen for determining types of jackpot bonus games. In this case, the display region  92  displays symbols of (1) to (5) made up of “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128”. These symbols are displayed so that the types of the jackpot bonus games can be selected through the selection of the symbols by the touch panel  69 . 
       FIGS. 8A and 8B  are diagrams each illustrating an exemplary image displayed in the slot machine  10  according to the first embodiment shown in  FIG. 2 , during the jackpot bonus game. As shown in  FIG. 8A , the jackpot bonus game corresponding to the symbol selected in  FIG. 7B  is displayed. In this case, since the symbol (2) is selected in  FIG. 7B , the jackpot bonus game of a car race is started, and a car-race start screen is displayed which constitutes the main character effect image  72  and the sub character effect image  73 . 
     As shown in  FIG. 8B , a win-or-loss screen of the jackpot bonus game corresponding to the symbol selected in  FIG. 7B  is displayed. In this case, when the symbol (2) is selected in  FIG. 7B  and the sub character effect image  73  wins in the jackpot bonus game of a car race, a win-or-loss information display  78   b  of “You Lose” is displayed. A payout display image  91   a  of “Mini” indicative of types of payouts of the jackpot is displayed, and the payout corresponding to “Mini” is awarded. 
       FIGS. 9A and 9B  are diagrams each illustrating an exemplary image displayed in the slot machine  10  according to the first embodiment shown in  FIG. 2 , during the jackpot bonus game. As shown in  FIG. 9A , when the symbol (2) is selected in  FIG. 7B  and the main character effect image  72  wins in the jackpot bonus game of a car race, a subsequent jackpot bonus game is started. In this case, the jackpot bonus game of a car race is started, and when the sub character effect image  73  wins, a win-or-loss information display  78   b  of “You Lose” is displayed. Further, a payout display image  91   b  of “Major” indicative of types of payouts of the jackpot is displayed, and a payout corresponding to “Major” is awarded. 
     As shown in  FIG. 9B , when the symbol (2) is selected in  FIG. 7B  and the main character effect image  72  wins in the jackpot bonus game of a car race, a subsequent jackpot bonus game is started. In this case, the jackpot bonus game of a car race is started, and when the main character effect image  72  wins, the win-or-loss information display  78   a  of “You Win” is displayed. Further, a payout display image  91   c  of “Mega” indicative of types of payouts of the jackpot is displayed, and a payout corresponding to “Mega” is awarded. 
     Next, a process executed in the slot machine  10  according to the first embodiment will be described in detail with reference to the drawings. The main CPU  41  controls the progress of a game by reading out and executing the game program. 
       FIG. 10  is a flowchart showing a subroutine of the main process. In the main process, first, when a power switch is turned on (that is, when power is supplied), a mother board  40  and a gaming board  50  are activated respectively, so that the CPU  51  executes an initial setting process (step S 101 ). In this initial setting process, the main CPU  41  executes the BIOS stored in the ROM  42 , decompresses, in the RAM  43 , compressed data included in the BIOS, executes the BIOS decompressed in the RAM  43 , and performs diagnosis and initialization of each of the peripheral devices. The main CPU  41  writes game programs or the like from the ROM  42  into the RAM  43 , and retrieves data for setting a payout ratio and country-identification information. The main CPU  41  also performs an authentication process for each program during execution of the initial setting process. 
     Next, the main CPU  41  performs a game execution process described later with reference to  FIG. 11  (step S 102 ). In this game execution process, the main CPU  41  sequentially reads and executes the game programs or the like from the ROM  42 . By performing this game execution process, the slot machine  10  according to the first embodiment  10  executes the game. The game execution process is repeatedly performed while power is supplied to the slot machine  10 . 
       FIG. 11  is a flowchart showing a subroutine of the game execution process invoked and performed at step S 102  of the subroutine shown in  FIG. 10  according to the first embodiment. First, the main CPU  41  judges whether a coin has been bet or not (step S 201 ). Specifically, the main CPU  41  judges whether or not an input signal has been received. The input signal is output from the 1-BET switch  26 S at the time of operation of the 1-BET button  26  or is output from the MAX-BET switch  27 S at the time of operation of the MAX-BET button. The main CPU  41  controls the current step to return to the process at step S 201  upon judging that no coin has been bet (step S 201 : NO). 
     On the other hand, the main CPU  41  subtracts the number of bet coins from the credit amount stored in the RAM  43  (step S 202 ) upon judging that a coin has been bet (step S 201 : YES). Where the number of bet coins is larger than the credit amount stored in the RAM  43 , the main CPU  41  controls the current step to return to step S 201  without performing the process for subtracting the number of bet coins from the credit number stored in the RAM  43 . Where the number of bet coins exceeds the upper limit (50 coins in this embodiment) of coins that can be bet in one game, the main CPU  41  controls the step to return to step S 203  without performing the process for subtracting the number of bet coins from the credit number stored in the RAM  43 . 
     At step S 203 , the main CPU  41  judges whether or not the start button  23  has been set to ON (step S 203 ). Specifically, the main CPU  41  judges whether or not an input signal output from the start switch  23 S when the start button  23  is pressed has been received. The main CPU  41  controls the step to return to step S 201  upon judging that the start button  23  has not been set to ON (step S 203 : NO). Where the start button  23  has not been set to ON (for example, where an instruction has been input to terminate the game without setting the start button  23  to ON), the main CPU  41  cancels acceptance of a subtraction result at step S 202 . 
     On the other hand, the main CPU  41  performs a symbol rearrangement process (step S 204 ) described later with reference to  FIG. 12  upon judging that the start button  23  has been set to ON (step S 203 : YES). Specifically, the main CPU  41  executes the program stored in the RAM  43  and determines the symbols to be rearranged in elements of the symbol matrix SM displayed on the lower image display panel  16 . The symbols are selected from among the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129”. This determination is based on the symbol weighing data and random numeric values sampled by sampling the random numeric values in a numeric-value range which comes under a predetermined range of random numeric values. The main CPU  41  then rearranges the symbols in the elements of the symbol matrix SM. 
     Next, the main CPU  41  judges whether a prize has been established or not (step S 205 ). Specifically, the main CPU  41  judges whether or not the number of symbols of respective types rearranged in the elements of the symbol matrix SM is a winning number allowed to award any of payouts. Herein, the prize is established on condition that a predetermined number of symbols of the same type are rearranged in the elements of the symbol matrix SM. 
     Upon judging that the prize is established (step S 205 : YES), the main CPU  41  then performs a coin-payout process in accordance with the amount of bet and the number of coins set for the winning number (step S 206 ). Where the coins are deposited, the main CPU  41  performs a process for adding the number of paid-out coins to the credit amount stored in the RAM  43 . On the other hand, upon execution of the coin-payout process, the main CPU  41  pays out the predetermined number of coins by transmitting a control signal to the hopper  66 . 
     Meanwhile, the main CPU  41  judges whether or not a free game trigger condition has been met (step S 207 ) upon judging that the prize is not established (step S 205 : NO) or upon executing the process at step S 206 . Specifically, the main CPU  41  executes the program stored in the RAM  43  to sample the random numeric values in a numeric-value range which comes under a predetermined range of random numeric values, thereby judging whether or not the free game trigger condition has been met based on the sampled random numeric values. Upon judging that the free game trigger condition has been met (step S 207 : YES), the main CPU  41  performs a free-game execution process described later with reference to  FIG. 14  (step S 208 ). In this free-game execution process, the main CPU  41  sequentially reads and executes the game programs or the like from the ROM  42  and performs the free-game execution process. 
     Meanwhile, the main CPU  41  judges whether or not a jackpot bonus game trigger condition has been met (step S 209 ) when judging that the free game trigger condition is not met (step S 207 : NO). Specifically, the main CPU  41  executes the program stored in the RAM  43  to sample the random numeric values in a numeric-value range which comes under a predetermined range of random numeric values, thereby judging whether or not the jackpot bonus game trigger condition has been met based on the sampled random numeric values. Upon judging that the jackpot bonus game trigger condition is met (step S 209 ), the main CPU  41  performs a jackpot bonus game execution process described later with reference to  FIG. 15  (step S 210 ). In this jackpot bonus game, the main CPU  41  sequentially reads and executes the game programs or the like from the ROM  42  and performs the jackpot bonus game execution process. 
     On the other hand, the CPU  41  terminates the game execution process when judging that the jackpot bonus game trigger condition is not met (step S 209 : NO) or when executing the process at step S 208 . 
       FIG. 12  is a flowchart showing a subroutine of the basic symbol rearrangement process invoked and performed at step S 204  of the subroutine shown in  FIG. 11 . First, the main CPU  41  displays the symbols in a scrolling manner (step S 301 ). Specifically, the main CPU  41  successively displays in a scrolling manner the symbols that are rearranged in the elements of the symbol matrix SM displayed on the lower image display panel. 
     Next, the main CPU  41  judges whether or not a side-BET has been set to ON (step S 302 ). Specifically, the main CPU  41  judges whether or not an input signal has been received, the signal being output from a side-BET switch  85 S when the side-BET button  85  is pushed. Upon judging that the side-BET button  85  has been set to ON (step S 302 : YES), the main CPU  41  executes a symbol combining process described later with reference to  FIG. 13  (step S 303 ). Specifically, the main CPU  41  reads at least two symbol image data including the symbol image data that have been combined on condition of an input of the side-BET, and reduces a horizontal or vertical direction of the symbol image data so as to be displayed in the region for displaying the single symbol. In this way, the combined symbol is rearranged. 
     On the other hand, upon judging that the side-BET has not been set to ON (step S 302 : NO), the main CPU  41  reads the rearranged symbol (step S 304 ). Specifically, the main CPU  41  selects a storage area, provided in the RAM  43 , of predetermined symbol data. Upon terminating this process, the main CPU  41  controls the step to move to step S 305 . 
     Next, upon terminating the process at step S 303  or step S 304 , the main CPU  41  rearranges the symbols (step S 305 ). Specifically, the main CPU  41  executes the program stored in the RAM  43  and determines the respective symbols to be arranged, which are judged at step S 303  or step S 304 , in the elements of the symbol matrix SM displayed on the lower image display panel. The symbols are selected from among the symbols “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129”, of which the last symbol is combined at step S 303 . This determination is based on the symbol weighing data and random numeric values sampled by sampling the random numeric values in a numeric-value range which comes under a predetermined range of random numeric values. The main CPU  41  then rearranges the symbols in the elements of the symbol matrix SM. Upon execution of this process, the main CPU  41  terminates the basic game symbol rearrangement process. 
       FIG. 13  is a flowchart showing a subroutine of the symbol combining process invoked and performed at step S 303  of the subroutine shown in  FIG. 12 . First, the main CPU  41  judges the rearranged symbols (step S 401 ). Specifically, the main CPU  41  selects the storage area, provided in the RAM  43 , of predetermined symbol data. 
     Next, the main CPU  41  judges whether or not the combined symbol is rearranged last time (step S 402 ). Specifically, the main CPU  41  judges whether or not the “combined symbol 129” is rearranged in the first display region  70  of the symbol matrix SM during the last basic game. Upon judging that the combined symbol is not rearranged last time (step S 402 : NO), the main CPU  41  judges whether or not the predetermined progressive value (step S 403 ) is obtained. Specifically, the main CPU  41  judges whether or not the value regarding the credit of the progressive jackpot is a predetermined value. Upon judging that the value is not the predetermined progressive value (step S 403 : NO), the main CPU  41  reads the symbol image data (step S 404 ). Specifically, from among the symbol image data stored in the RAM  43 , the main CPU  41  reads two symbol image data that are combined with each other. Upon terminating this process, the main CPU  41  controls the step to move to step S 406 . 
     On the other hand, upon judging that the value is the predetermined progressive value (step S 402 : YES), the main CPU  41  reads the jackpot symbol image data and the symbol image data (step S 405 ). Specifically, from among the image data stored in the RAM  43 , the main CPU  41  reads the two items of image data, i.e., the image data of the jack pot symbol and that of the symbol to which the jackpot symbol is added. 
     Next, the main CPU  41  refers to a size of the symbol matrix display region (step S 406 ). Specifically, the main CPU  41  refers to a size of the element of the display region of the symbol matrix SM in which the combined symbol is rearranged. 
     Next, the main CPU  41  reduces the symbol image data (step S 407 ). Specifically, the main CPU  41  reduces a horizontal or vertical direction of the symbol image data read to match the size referred at step S 406  so that the two symbol images read at step S 405  are displayed in the region for displaying a single symbol. 
     Next, the main CPU  41  generates the combined symbol image data (step S 408 ). Specifically, based on the symbol image data reduced at step S 407 , the main CPU  41  generates the combined symbol image data for rearranging the combined symbol in the first display region  70  of the symbol matrix SM (see  FIG. 1A ). 
     On the other hand, upon judging that the combined symbol is rearranged last time (step S 402 : YES), the main CPU  41  changes a scaling ratio (step S 409 ). Specifically, the main CPU  41  changes the scaling ratio of the symbol image data so that the area ratios of the respective image data of the combined symbol change according to the number of times in executing the basic games (see  FIG. 1B ). 
     Next, the main CPU  41  judges whether or not a predetermined number of games is reached (step S 410 ). Specifically, the main CPU  41  judges whether or not the predetermined number of basic games is reached from a time when the combined symbol is rearranged. Upon judging that the predetermined number of games is not reached (step S 410 : NO), the main CPU  41  terminates the symbol combining process. 
     On the other hand, upon judging that the predetermined number of games is reached (step S 410 : YES), the main CPU  41  reads the single symbol image data (step S 411 ). Specifically, the main CPU  41  judges whether or not the predetermined number of games is reached from a time when the combined symbol is rearranged. Upon judging that the predetermined number of games is not reached (step S 410 : NO), the main CPU  41  terminates the symbol combining process. 
     On the other hand, upon judging that the predetermined number of games is reached (step S 410 : YES), the main CPU  41  reads the single symbol image data (step S 411 ). Specifically, in order to transform the combined symbol into the single symbols by gradually changing the area ratio of the respective symbols of the combined symbol according to the number of times in executing the basic games at step S 409 , the main CPU  41  reads the single symbol, based on the combined symbol (see  FIG. 1C ). Upon terminating the process at step S 411 , the main CPU  41  terminates the symbol combining process. 
       FIG. 14  is a flowchart showing a subroutine of the free-game execution process invoked and executed at step S 208  of the subroutine shown in  FIG. 11 . First, the main CPU  41  determines the free-game number T (step S 501 ). Specifically, the main CPU  41  determines the free-game number T in accordance with the program stored in the RAM  43 . 
     Next, the main CPU  41  performs a process for setting the free-game number B=T (step S 502 ). Specifically, the main CPU  41  sets a remaining free-game number B=T in a storage area, provided in the RAM  43 , of data indicative of the remaining free-game number B=T. T is the free-game number determined at step S 401 . 
     Next, the main CPU  41  judges whether or not the start button  23  has been set to ON (step S 503 ). Specifically, the main CPU  41  judges whether or not an input signal output from the start switch  23 S when the start button  23  is pushed has been received. The main CPU  41  controls the step to return to step S 403  upon judging that the start button  23  has not been set to ON (step S 503 : NO). 
     On the other hand, upon judging that the start button  23  has been set to ON (step S 503 : YES), the main CPU  41  performs a process for displaying the effect image (step S 504 ). Specifically, the main CPU  41  displays the free-game-number display image  90   a  corresponding to the number of times in executing the free game on the upper image display panel  33  (see  FIG. 6A ). 
     Next, the main CPU  41  performs a process for rearranging symbols in the free game (step S 505 ). Specifically, the main CPU  41  executes the program stored in the RAM  43  and determines the symbols to be rearranged in elements of the symbol matrix SM  28  displayed on the lower image display panel. These symbols are selected from among the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, “villa 128”, and “combined symbol 129”. This determination is based on the symbol weighing data and random numeric values sampled by sampling the random numeric values in a numeric-value range which comes under a predetermined range of random numeric values. The main CPU  41  then rearranges the symbols to be rearranged in the elements of the symbol matrix SM. 
     Next, the main CPU  41  judges whether a jackpot bonus trigger condition has been met or not (step S 506 ). Specifically, the main CPU  41  executes the program stored in the RAM  43  to sample the random numeric values in a numeric-value range which comes under a predetermined range of random numeric values, thereby judging whether or not the jackpot bonus game trigger condition has been met based on the sampled random numeric values. The main CPU  41  controls the step to move to step S 508  upon judging that the jackpot bonus game trigger condition has been met (step S 506 : NO). 
     On the other hand, upon judging that the jackpot bonus trigger condition has been met (step S 506 : YES), the main CPU  41  executes a jackpot bonus game execution process described later with reference to  FIG. 15  (step S 507 ). In this jackpot bonus game, the main CPU  41  sequentially reads and executes the game programs or the like from the ROM  42  and performs the jackpot bonus game execution process. 
     Next, the main CPU  41  judges whether a prize has been established or not (step S 508 ). Specifically, the main CPU  41  judges whether or not the number of symbols of respective types rearranged in the elements of the symbol matrix SM is a winning number allowed to award any of payouts. Herein, the prize is established on condition that a predetermined number of symbols of the same type are rearranged in the elements of the symbol matrix SM. 
     Thereafter, upon judging that the prize has been established (step S 508 : YES), the main CPU  41  performs a payout process for paying out the coins in accordance with the number of coins set for the winning number (step S 509 ). Where the coins are deposited, the main CPU  41  performs a process for adding the number of paid-out coins to the credit amount stored in the RAM  43 . On the other hand, upon execution of the coin-payout process, the main CPU  41  pays out the predetermined number of coins by transmitting a control signal to the hopper  66 . 
     On the other hand, upon judging that the prize has not been established (step S 508 : NO) or upon executing the processes at step S 509 , the main CPU  41  sets the remaining free-game number B=B−1 (step S 510 ). Specifically, the main CPU  41  sets B=B−1 at a value of the remaining free-game number B stored in the RAM  43 . 
     The main CPU  41  then judges whether or not a value of the remaining free-game number B is equal to zero (step S 511 ). Specifically, the main CPU  41  judges whether or not a value of the remaining free-game number B stored in the RAM  43  is equal to zero. Upon judging that the value of the remaining free-game number B is not zero (step S 511 : NO), the main CPU  41  controls the step to return to step S 503 . 
     On the other hand, upon judging that the value of B is equal to zero (step S 511 : YES), the main CPU  41  terminates the free-game execution process. 
       FIG. 15  is a flowchart showing a subroutine of the jackpot bonus game execution process invoked and performed at step S 210  of the subroutine shown in  FIG. 11  and at step S 507  of the subroutine shown in  FIG. 14 . At first, the main CPU  41  displays a first effect selection image (step S 601 ). Specifically, the main CPU  41  displays the jackpot bonus game display image  90   b  displaying the start of the jackpot bonus game on the upper image display panel  33 , and a selection screen for determining the types of jackpot bonus games in the display region  92  (see  FIG. 7B ). 
     Next, the main CPU  41  judges whether or not the symbol is selected (step S 602 ). Specifically, the main CPU  41  judges whether or not the symbol displayed on the selection screen for determining the types of jackpot bonus games is selected via the touch panel  69 . Upon judging that the symbol is not selected (step S 602 : NO), the main CPU  41  controls the step to return to step S 502 . 
     On the other hand, upon judging that the symbol is selected (step S 602 : YES), the main CPU  41  displays the selected effect image (step S 603 ). Specifically, the main CPU  41  sequentially reads the effect image corresponding to the symbol selected at step S 502  from the ROM  42  and displays the effect image in the display region  92  (see  FIG. 8A ). 
     Next, the main CPU  41  judges whether or not the side-BET has been set to ON (step S 604 ). Specifically, the main CPU  41  judges whether or not an input signal has been received, the signal being output from the side-BET switch  85 S when the side-BET button  85  is pushed. Upon judging that the side-BET button  85  has not been set to ON (step S 604 : NO), the main CPU  41  displays an effect images of “Lose” (step S 605 ). Specifically, the CPU  41  reads the effect image corresponding to the effect image of “Lose” from the ROM  42 , and displays the effect image in the display region  92  (see  FIG. 8B ). Next, the main CPU  41  executes a payout process of Mini (step S 606 ). Specifically, the main CPU  41  performs the coin payout process corresponding to “Mini”. Where the coins are deposited, the main CPU  41  performs a process for adding the number of paid-out coins to the credit amount stored in the RAM  43 . On the other hand, upon execution of the coin-payout process, the main CPU  41  pays out the predetermined number of coins by transmitting a control signal to the hopper  66 . Upon execution of the process at step S 606 , the main CPU  41  terminates the jackpot bonus game execution process. 
     On the other hand, upon judging that the side-BET has been set to ON (step S 604 : YES), the main CPU  41  displays an effect image of Win and displays a second effect selection image (step S 607 ). Specifically, the main CPU  41  displays in the display region  92  a selection screen for determining the types of jackpot bonus games so that the symbol selected at step S 602  is identifiable. 
     Next, the main CPU  41  judges whether or not the predetermined symbol is selected (step S 608 ). Specifically, the main CPU  41  judges whether or not the symbol other than that selected at step S 602  is selected by way of the symbol touch panel  69 . Upon judging that the predetermined symbol is not selected (step S 608 : NO), the main CPU  41  controls the step to return to step S 608 . 
     On the other hand, upon judging that the predetermined symbol is selected (step S 608 : YES), the main CPU  41  displays the selected effect image (step S 609 ). Specifically, the main CPU  41  sequentially reads the effect image corresponding to the symbol selected at step S 602 , from the ROM  42 , and displays the effect image in the display region  92 . 
     Next, the main CPU  41  judges whether or not the “Win” effect is read (step S 610 ). Specifically, the main CPU  41  judges whether or not the effect image read at step S 609  is the “Win” effect. Upon judging that the Win effect is not read (step S 610 : NO), the main CPU  41  displays the effect image of “Lose” (step S 611 ). Specifically, the main CPU  41  reads the effect image corresponding to the effect image of “Lose” from the ROM  42  and displays the effect image in the display region  92  (see  FIG. 9A ). Next, the main CPU  41  executes a payout process of “Major” (step S 612 ). Specifically, the main CPU  41  performs the coin payout process corresponding to “Major”. Where the coins are deposited, the main CPU  41  performs a process for adding the number of paid-out coins to the credit amount stored in the RAM  43 . On the other hand, upon execution of the coin-payout process, the main CPU  41  pays out the predetermined number of coins by transmitting a control signal to the hopper  66 . Upon execution of the process at step S 612 , the main CPU  41  terminates the jackpot bonus game execution process. 
     On the other hand, upon judging that the Win effect is read (step S 610 : YES), the main CPU  41  displays the effect image of “Win”. Specifically, the main CPU  41  reads the effect image corresponding to the effect image of “Win” from the ROM  42  and displays the effect image in the display region  92  (see  FIG. 9B ). Next, the main CPU  41  executes a payout process of “Mega” (step S 614 ). Specifically, the main CPU  41  performs the coin-payout process corresponding to “Mega”. Where the coins are deposited, the main CPU  41  performs a process for adding the number of paid-out coins to the credit amount stored in the RAM  43 . On the other hand, upon execution of the coin-payout process, the main CPU  41  pays out the predetermined number of coins by transmitting a control signal to the hopper  66 . Upon execution of the process at step S 614 , the main CPU  41  terminates the jackpot bonus game execution process. 
     Next, a slot machine  100  according to a second embodiment will be described with reference to the drawings. The slot machine according to the second embodiment described below is a so-called hybrid slot machine in which a plurality of rotatably-supported mechanical reels have a transparent liquid crystal panel on front surfaces to display images of various symbols drawn on peripheral surfaces of the mechanism reels through the transparent liquid crystal panel through which the pictures are allowed to pass. The slot machine according to the second embodiment has an appearance, circuitry, and the like that are substantially the same as those of the slot machine  10  according to the first embodiment. Thus, a duplicated explanation is omitted here. Constituent elements corresponding to those of the slot machine  10  are designated by the same reference numerals and are explained. 
       FIG. 16  is a view schematically showing an appearance of a frame format of the slot machine according to the second embodiment of the present invention. As shown in  FIG. 16 , the slot machine  100  is rotatably provided with three reels  101   a  to  101   c.  A symbol column made up of the symbols, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128” is drawn on the respective one of the outer circumferential surfaces of the reels  101   a  to  101   c.    
     A main liquid crystal panel  202  formed of a transparent liquid crystal panel, which is disposed at the main door, is provided in front of the respective reels  101   a  to  101   c.  The main liquid crystal panel  202  displays the symbol display region  28  with visually recognizable rear surface so as to surround symbols which were drawn on the reels  101   a  to  101   c  and displayed in a stopped state, respectively. The symbols drawn on the reels  101   a  to  101   c  are visualized by rendering the symbol display region  28  transparent. 
       FIGS. 17A ,  17 B, and  17 C are views each showing an exemplary symbol matrix during a basic game. As shown in  FIGS. 17A to 17C , the symbol display region  28  is displayed on the main liquid crystal panel  202  provided in the slot machine  100  of the present invention. A total of three reels  101   a  to  101   c  are rotatably provided rearwardly of the liquid crystal panel  202 . Six basic lines BL are set along each row or each column in the symbol display region  28 . In the embodiment of the present invention, the basic line means a wining line other than a cross line. Two cross lines CL are set which diagonally cross the symbol display region  28 . Eight winning lines in the embodiment of the present invention include the basic lines BL and the cross lines CL. When a predetermined symbol is rearranged on the bet winning line, a LIN payment is awarded based on a winning combination, and then, an ANY payment is awarded according to the number of symbols rearranged in the symbol display region  28 . 
     As shown in  FIG. 17A , when the reels  101   a  to  101   c  stop, any of a total of nine symbols in three rows and three columns, “main character 121”, “sub character 122”, “office building 123”, “gold bullion 124”, “car 125”, “stock certificate 126”, “jet 127”, and “villa 128”, are displayed in a stopped state. When a predetermined trigger condition is met, with the use of the liquid crystal panel  202 , the “combined symbol 129”, in which at least two symbol images combined on condition that the side-BET is input are used to display a single symbol, is rearranged to be superposed on the reels  101   a  and  101   b.  In this case, after the reels  101   a  and  101   b  are displayed in a stopped state, the “combined symbols 129” are rearranged to be superposed with the use of the liquid crystal panel  202  in display windows  103   a  and  103   e.  Thereafter, the reel  101   c  is displayed in a stopped state, and the “sub character 122” is rearranged. 
     As shown in  FIG. 17B , area ratios of the respective symbols of the combined symbol, i.e., the “combined symbol 129” displayed on the liquid crystal panel  202  within the symbol display region  28  on the lower image display panel  16  in  FIG. 17A  are changed during a predetermined basic game according to the number of times in executing the basic games. In this case, according to the number of times in executing the basic games, a scaling ratio in a horizontal direction between the main character  121  and the sub character  122  or jackpot symbol is changed so that the symbol of the main character  121  added to the “combined symbol 129” is rearranged more widely or the symbol of the sub character  122  or jackpot symbol is rearranged more widely. In this way, the “combined symbol 129” is changed. 
     As shown in  FIG. 17C , the area ratios of the respective symbols of the combined symbol are changed in  FIG. 1B . Thereafter, according to types of the combination of the changed “combined symbol 129” displayed on the liquid crystal panel  202  and the single symbol displayed in a stopped state in the symbol display region  28 , one bonus game is selectively executed from among a plurality of bonus games. In this case, since a winning combination of three sub characters  122  is rearranged, the payment is awarded based on the winning combination. Then, according to types of the winning combination, the jackpot bonus game is selected and executed. 
     In the foregoing, while the embodiments of the present invention have been described, these embodiments merely present specific examples. An appropriate design change can be made for the specific configuration of each means or the like. Also, the effects described in the embodiments of the present invention are only listing the most preferable effects arising from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.