Abstract:
A game machine of a type playing a game by collecting a character electronically generated has a property data storage region storing property data of the collected character and a program storage region storing game programs. A random number is generated, and is compared with a part or the whole of the property data. When the part or the whole of the property data and the random number are in a predetermined relationship, image processing is performed for displaying a screen indicating a winning.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to game machines and information storage media storing game programs. More specifically, it relates to a game machine allowing, in a video game machine or a portable game machine simulating the for capturing, training and exchanging characters including those which appear to be monsters, a lottery by the properties of the characters, and an information storage medium storing a game program therefor. 
     2. Description of the Background Art 
     Conventionally, a game referred to as “Pocket Monster (red, green, blue and yellow versions)” (trade name; hereinafter referred to as “prior art”) designed or sold by the assignee of the applicants of the present invention has been available. The game disclosed in the prior art is for capturing, training, and exchanging characters (hereinafter referred to as either or characters). In the game, the probability of appearance of a monster is set differently for each version. A player attempts to capture or collect the maximum number of monsters and is able to exchange the monsters with friends. 
     Referring to a block diagram of FIG. 11, description is made of the configuration of a conventional image-display game machine according to the prior art. A conventional image-display game machine GBC roughly comprises a program source  100 C and a game machine  200 . The program source  100 C stores information such as programs required to play the image-based display game on the game machine  200 , and is so constructed that it can be connected to the game machine  200  in a detachable manner. 
     The program source  100 C is preferably constructed as a cartridge comprising a ROM  11 C, a RAM  12 C, a memory bank controller  15 , and a connector  13 . The ROM  11 C is constituted by non-volatile memory such as ROM, flash memory, and EE-PROM, and fixedly stores the game programs. The ROM  11 C stores programs which, taken together, define the contents of a game. For example, a capturing program, a training program, and so forth are stored if the game is for capturing and training monsters characters such as. The ROM  11 C also stores dot data of an image representing each of the monsters, and further, a program for exchanging data among other game machines  200 , as required. 
     The RAM  12 C is constituted by readable/writable RAM memory, and includes a region storing a plurality of types of property data of a plurality of characters which have been obtained during to the progress of the game. 
     The memory bank controller  15  divides a memory chunk of the ROM  11 C into a plurality of banks when the memory chunk is too large for an address bus to address, and generates bank data for the higher address in the ROM  11 C and for addressing a memory chunk of the RAM  12 C. The ROM  11 C, the RAM  12 C, and the memory bank controller  15  are connected to the game machine  200  via the connector  13  in a detachable manner. 
     The game machine  200  mainly comprises an operation switch portion  22 , a central processing unit (CPU)  23 , a connector  24 , a RAM  25 , a display controller  26 , a liquid crystal display (LCD)  27 , an interface  28 , and a connector  29 . The RAM  25  serving as working memory to temporarily store data for processing during the game and the display control circuit  26  are connected to the CPU  23 . The liquid crystal display  27  is connected to the display controller  26 . Further, the connector  29  is connected to the CPU  23  through the interface circuit  28 . The connector  29  is connected to another connector  29  of another game machine  200  through a cable when the player exchanges the obtained monsters with another player who is an owner of the other game machine  200 . The CPU  23  is connected with the program source  100 C via the connector  24 . 
     Referring now to FIG. 12, the structure of a storage region of the RAM  12 C will be described in detail. The storage region of the RAM  12 C includes an obtained Pokemon data region DAamC and an environmental data region DoC. The obtained Pokemon data region DAamC stores data for defining each of the obtained game characters, or Pokemons, and properties thereof. The obtained Pokemons are respectively recorded and identified as records R 1  to RN (N is a natural number). Each of the records R has fields I 1  to I 9  storing items for defining the obtained Pokemon. 
     The field I 1  stores a monster code (or a Pokemon number) assigned for each type of Pokemon. 
     The field I 2  stores hit points (HPs) of the Pokemon. 
     The field I 3  stores experience points of the Pokemon. 
     The field I 4  stores a level of the Pokemon. 
     The field I 5  stores a status of the Pokemon. 
     The field I 6  stores technique (possible attack) data of the Pokemon. 
     The field I 7  stores a player ID representing a player. 
     The field I 8  stores Pokemon&#39;s ability value such as attack power, defense power, special attach power, special defense power, and quickness. 
     The field I 9  is a spare field for storing data other than the items stored in the fields I 1  to I 8 . 
     As described above, the obtained Pokemons are respectively defined by the records R 1  to RN, and the properties of each of the Pokemons are defined by the fields I 1  to I 9 . That is, a property of an arbitrarily obtained Pokemon is represented as P (Rn, Im) (n is a natural number of not more than N, and m is a natural number of not more than 9). However, data representing the properties stored in the fields I 1  to I 9  do not make it possible to run a lottery. 
     The environmental data region DoC stores environmental data required for the progress of the game, for example, a location, a time when the game is played, and a player name. The environmental data region DoC does not store data for making it possible to run a lottery. 
     As described above, according to the prior art video game, there is enjoyment in the game from collecting monsters. However, it is impossible to perform a lottery on the basis of property data corresponding to the collected monsters. 
     Therefore, an object of the present invention is to provide a game machine and an information storage medium storing a game program therefor capable of giving further variety to a game and further increasing amusement in the game by incorporating an element of lot drawing into the game, and further, encouraging the players to exchange the monsters. 
     SUMMARY OF THE INVENTION 
     A first aspect of the present invention is directed to a game machine of a type playing a game by collecting a character electronically generated, comprising: 
     a property data storage for storing property data of the collected character; 
     a program storage for storing a game program; 
     a random number generator for generating a random number; 
     a comparator for comparing a part or the whole of the property data stored in the property data storage with the random number; and 
     a processor for performing, when the comparator determines that the part or the whole of the property data and the random number are in a predetermined relationship, image processing for displaying a screen indicating winning. 
     As described above, in the first aspect, an event can be carried out in a random manner on the basis of the properties of the collected characters. 
     According to a second aspect, in the first aspect, the game machine can store, in the property data storage, the property data of the character which is transmitted from another game machine by communicating with the other game machine. 
     As described above, in the second aspect, the characters can be also collected from the other game machine, thereby making it possible to increasingly diversify the property of the character. 
     According to a third aspect, in either one of the first or second aspect, the property data includes a variable property which can change and an invariable property which does not change after the character is collected. 
     As described above, in the third aspect, the property data is both variable and invariable. Accordingly, the events can be carried out in more variations. 
     According to a fourth aspect, in the third aspect, the invariable property is a code assigned to a user who is registered in the program storage. 
     As described above, in the fourth aspect, the property data is invariable. Accordingly, the property data of the character is obtained from the other game machine, thereby increasingly diversifying the events. 
     According to a fifth aspect, in the third aspect, the invariable property is a code assigned for identifying a type of the character. 
     According to a sixth aspect, in the third aspect, the variable property is arbitrarily selected out of a character number, and hit points, experience points, a level, a status, a possible attack, an ability value, an item, and a virus-infection of the character. 
     According to a seventh aspect, in the third aspect, the variable property is data for defining a character which grows and changes. 
     An eighth aspect is directed to a medium storing a game program for controlling a game machine of a type playing a game by collecting a character electronically generated, wherein 
     the game program makes said game machine to carry out the steps of: 
     storing property data of the collected character; 
     generating a random number; 
     comparing a part or the whole of the stored property data with the random number; and 
     performing, when the part or the whole of the property data and the random number are determined to have a predetermined relationship in the comparing step, image processing for displaying a screen indicating a winning. 
     According to a ninth aspect, in the eighth aspect, the game program is stored in ROM, and the property data is stored in nonvolatile memory. 
     These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing the configuration of an image-display game machine according to the present invention; 
     FIG. 2 is a schematic view showing the structure of a storage region of a ROM shown in FIG. 1; 
     FIG. 3 is a schematic view showing the structure of a storage region of a RAM shown in FIG. 1; 
     FIG. 4 is an explanatory view showing an example of a map of a game played on the image-display game machine according to the present invention; 
     FIG. 5 is a diagram showing a battle state in the game played on the image-display game machine according to the present invention; 
     FIG. 6 is a diagram showing the appearance of a portable game machine serving as an example of the image-display game machine according to the present invention; 
     FIG. 7 is a flow chart showing the main operation of the image-display game machine shown in FIG. 1; 
     FIG. 8 is a flow chart showing a part of the detailed operation in a lottery processing sub-routine shown in FIG. 7; 
     FIG. 9 is a flow chart showing the remaining part of the detailed operation in the lottery processing sub-routine partially shown in FIG. 8; 
     FIG. 10 is a flow chart showing a part of the detailed operation in a communication processing sub-routine shown in FIG. 7; 
     FIG. 11 is a block diagram showing the configuration of a conventional image-display game machine; and 
     FIG. 12 is a schematic view showing the structure of a storage region of a RAM shown in FIG.  11 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, an image-display game machine GBP according to the present embodiment comprises a program source  100  and a game machine  200 , which may, for example, be a game machine such as has been described above in conjunction with FIG.  11 . The program source  100  stores information such as programs required to play the image-display game on the game machine  200 , and is so constructed that it can be detachably connected to the game machine  200 . 
     The program source  100  is preferably constructed as a cartridge comprising a ROM  11 , a RAM  12 , a clock  14 , and a memory bank controller  15 . The ROM  11  is constituted by nonvolatile memory such as ROM, flash memory, and EE-PROM, and fixedly stores the game program. The ROM  11  stores programs which taken together, define the contents of a game. For example, a capturing program, a training program, and so forth are stored if the game is of a type which simulates capturing and training monsters. 
     Furthermore, the ROM  11  stores dot data of an image representing each of the monsters, a program for exchanging data, as required, among other portable game machines  200  (not shown), and a program for ensuring compatibility with the program stored in the program source  100 C of the conventional image-display game machine GBC shown in FIG.  11 . 
     Hereinafter, when the program source  100  (a new cartridge) and the conventional program source  100 C (a cartridge which has already been put on the market) need not be particularly distinguished from each other, both are generically referred to as a cartridge  100 . 
     The RAM  12  is constituted by a readable/writable memory which is represented by RAM, and includes a region storing a plurality of types of property data of a plurality of characters which have been obtained in relation to the progress of the game. 
     Referring now to FIG. 2, the structure of a storage region of the ROM  11  will be described in detail. The storage region of the ROM  11  in the present embodiment broadly includes a program region, an image data region, a Pokemon data region, a sound memory region, a Pokemon appearance probability table storage region, a zone map storage region, and other regions. 
     Herein, a time-varying factor such as time and time zone is introduced into the Pokemon data region, the sound memory region, and the Pokemon appearance probability table storage region out of the main regions. 
     FIG. 4 illustrates an example of a game map which is displayed on the game machine  200  based on the image data stored in the image data region. 
     An example of a battle state in a game which is developed in the image-display game machine according to the present invention is illustrated in FIG.  5 . 
     Referring now to FIG. 3, the structure of a storage region of the RAM  12  will be described in detail. The storage region of the RAM  12  includes an obtained Pokemon data region DAamP and an environmental data region DoP in the present embodiment. The obtained Pokemon data region DAamP is the same as the obtained Pokemon data region DAamC in the conventional RAM  12 C in that it stores the obtained game characters, or the Pokemons and data representing the properties thereof. That is, the obtained Pokemon data region DAamP includes the records R 1  to RN each comprising the fields I 1  to I 9  included in the obtained Pokemon data region DAamC. 
     In the obtained Pokemon data region DAamP, however, each of the records R is newly provided with at least four fields J 1 , J 2 , J 3 , and J 4  in addition to the conventional fields I 1  to I 9 . 
     The field J 1  stores the sex of the obtained Pokemon. 
     The field J 2  stores item(s) owned by the obtained Pokemon. 
     The field J 3  stores a state indicating whether or not the obtained Pokemon is infected with a virus. A monster which is infected with the virus has a scarcity value. For example, the speed which the HP, experience points, level, ability value or the like increases through training of a monster which is infected with the virus is controlled to be faster and/or higher than that of a monster which is not infected with the virus. 
     The field J 4  is a spare field for storing data other than the items stored in the fields J 1  to J 3 . 
     In the present embodiment, O (O is a natural number) arbitrary fields J 1  to JO may be provided, as required, in place of the four fields J 1  to J 4 . 
     The fields I 1  to I 9  are storage regions which are equally assigned to the conventional program source  100 C and the program source  100  according to the present invention. Consequently, the program source  100 C (RAM  12 C) and the program source  100  (RAM  12 ) have compatibility. On the other hand, the fields J 1  to J 4  are regions which are uniquely assigned to the program source  100  (RAM  12 ) according to an exemplary embodiment the present invention. 
     In the exemplary embodiment present invention, the monster is set to evolve or grow up to improve the ability thereof as the game progresses, and is soon changed into another type of monster. Such a change is realized by changing the monster code stored in the field I 1  into another monster code. 
     In the exemplary embodiment present invention, the obtained Pokemons are respectively defined by the records R 1  to RN, and the properties of each of the Pokemons are defined by the fields I 1  to I 9  and the fields J 1  to J 4 . That is, the properties of the obtained Pokemon are represented as P (Rn, Im) or P (Rn, Jo) (o is a natural number of not more than four). 
     The environmental data region DoP is provided with a region DoN storing environmental data relating to the data newly set in the ROM  11  in the present invention, in addition to the environmental data region DoC shown in FIG.  12 . The new region DoN stores data newly added in the present invention such as variables A, B 1 , B 2 , B 3 , etc. and items that are won in a lottery. 
     Returning to FIG. 1, the clock  14  includes at least a timer for measuring time, and includes a calendar function for indicating a date (month and day) and a day of the week, as required. 
     The memory bank controller  15  divides a memory chunk of the ROM  11  into a plurality of banks when the memory chunk is too large for an address bus to address, and generates bank data for the higher address in the ROM  11  and for addressing a memory chunk in the RAM  12 . 
     Preferably, the clock  14  and the memory bank controller  15  are implemented in a single chip of an integrated circuit (IC) to reduce the number of chips, resulting in lower cost. A substrate on which the single chip IC including the ROM  11  and the RAM  12  is mounted is accommodated in a case or a housing. 
     The game machine  200  is the same as that already described in detail with reference to FIG.  11 . 
     FIG. 6 illustrates an example in which the image-display game machine GBP according to the present invention is constructed as a portable game machine. In the image-display game machine GBP, the connector  13  (FIG. 1) of the cartridge  100  is engaged to the connector  24  (FIG. 1) provided on a rear surface of the game machine  200 . An operation switch portion  22  is provided on a lower-end side of a front surface (plane) of a housing  21  of the game machine  200 , and a liquid crystal display  27  is provided on an upper part thereof. A circuit board composed of the circuit components shown in FIG. 1 is provided in the housing  21 . 
     The operation switch  22  comprises a direction switch  22   a  for designating cursor movements or directions of movement of a character which can be operated by a player, an action switch  22   b  for designating character&#39;s action including movement, a start switch  22   c,  and a select switch  22   d.    
     Description is now made of the operation of the image-display game machine according to an exemplary embodiment of the present invention. When a player presses the start switch  22   c,  a game is started. After a title screen is displayed, some area of the game map shown in FIG. 4 is displayed as a screen when the game starts. 
     In order to capture a monster, a player operates the direction switch  22   a  to move a player character (or a player object) to a probable location on the game map where the monster is hiding. For example the type of the monster lives in water, the location where the monster is hiding is a pond, a sea, or the like. If the type of the monster is plant-eating, the location where the monster is hiding is a grassy area, a farm, woods, or the like. 
     When the player captures a monster or exchanges a monster with a friend, the data items of the monster are stored in the corresponding fields I 1  to I 9  and J 1  to J 4  in the unused record Rn of the obtained Pokemon data region DAamP. As described with reference to FIG. 3 (FIG.  12 ), the monster code of the captured monster is written into the field I 1  and at the same time, the hit points (HPs), the experience points, the level, the status, the possible attack, the ability, and the like which the monster has at the point in time where it is captured are respectively stored in the fields I 2 , I 3 , I 4 , I 5 , I 6 , I 7 , and I 8 . 
     With respect to a monster obtained from a friend, the player ID stored in the field I 7  is an ID assigned to the friend or another player from whom the friend previously obtained the monster. That is, if the exchange of the monsters is repeated, it is possible to obtain a lot of monsters having different player IDs. 
     If the cartridge used by the player is the program source  100  according to an exemplary embodiment of the present invention, character property data such as sex data, item data, virus-infection data, and so forth for each monster, are respectively stored in the fields J 1  to J 3 . The monster which is infected with the virus is of scarcity value. The speed at which the HP, the experience points, the level, the ability value, or the like, of the virus-infected monster increases by training is set faster than that of a monster which is not infected with the virus. 
     Consequently, the player attempts to infect captured monsters with the virus in order to quickly grow or train the monsters. Therefore, the player searches for and captures the monster which is infected with the virus, puts a monster which is not infected with the virus in a incubation box (incubation room) together with the virus-infected monster for infection, thereby speeding up the growth of the monster. 
     It is thus possible to speed up the growth of the monster and shorten training time required for raising the monster&#39;s level to a certain level by utilizing the event of viral-infection that speeds up the growth or the rise in level. 
     When the game is played using the game cartridge provided with the program source  100 , data representing sex is provided to monsters. When the male and female monsters of the same type (monster code) out of the captured monsters are paired and are put in the incubation box (incubation room), the time or the date at that time is temporarily stored in a register. When a predetermined number of days have elapsed as determined by a program is counted starting from the registered time or date by the clock  14 , a baby monster inheriting the property data (ability, strength, etc.) from both the male and female monsters is born, thereby making it possible to increase the number of types of collected monsters. 
     It is thus easy to collect various types of monsters, so that the progress of the game can be sped up, and the player can experience the enjoyment and expectation of training the baby monster from the beginning of its development. When a plurality of monsters of the same type are captured, the player can exchange any one of the monsters with one, which he or she does not own, of a plurality of another type monsters which are captured by a friend. 
     When an owner of a new cartridge provided with the program source  100  which is a new version and an owner of an old cartridge provided with the conventional program source  100 C exchange monsters, it is desirable that compatibility between the program sources is ensured as much as possible with respect to the handling of the data representing sex, items, virus-infection, and so forth which should be stored in the fields J 1  to J 3 . For the sake of compatibility, when transferring the data from the new cartridge to the old cartridge, one-bit data indicating the presence of the data for the fields J 1  to J 3  is stored in the field I 9 . 
     When the game is played thereafter, using the old cartridge, the game progresses without using the additional data representing sex, items, virus-infection, and so forth. When the data is transferred back from the old cartridge to the new cartridge, the one-bit data stored in the field I 9  is also transferred. When the owner of the new cartridge plays the game, therefore, the game can be played using the additional data. 
     Conversely, when the data is transferred from the old cartridge to the new cartridge, data representing sex, for example, which is not stored in the old cartridge is determined in accordance with a predetermined rule, and is written into the field J 1  in the new cartridge. As an exemplary rule, the sex may be determined to be male if the one place number of the “minutes” of time measured by the clock  14  is odd, while being female if it is even. Alternatively, determination may be made based on a random number. 
     As such, even when the monsters are exchanged between the old cartridge and the new cartridge, compatibility can be ensured as much as possible, so that the data can be exchange among all players. Further, when the player who owns the old cartridge purchases the new cartridge, the monster which has been trained in the old cartridge can be transferred to the new cartridge as it is, thereby making it possible to effectively make use of the monster which has been previously trained in the old cartridge. 
     The monsters newly captured by the player, the monster newly born from the couple of the obtained monsters, and the monsters exchanged with the friends are all used for battles with the friend&#39;s monsters. The battle is done by connecting the connectors  29  of the game machines  200  each owned by the player and friend using a cable, and putting each monster designated by the player and friend in a battle field. FIG. 5 illustrates an example of the battle state. 
     Referring now to a main flow chart of FIG. 7, description follows of the main operation of the image-display game machine GBP according to an exemplary embodiment the present invention. Thereafter, a lottery processing sub-routine in step # 600  shown in FIG. 7 will be specifically described with reference to detailed flow charts of FIGS. 8 and 9. 
     As shown in the main flow chart of FIG. 7, to begin the player presses the start switch  22   c,    
     in step # 100 , game-start processing is executed. The procedure then proceeds to a subsequent step # 200 . 
     In step # 200 , a player object processing sub-routine is executed. The procedure then proceeds to a subsequent step # 300 . 
     In the step # 300 , an object processing sub-routine for the objects other than the player object is executed. The procedure then proceeds to a subsequent step # 400 . 
     In step # 400 , a background image processing sub-routine is executed. Through the processing in the foregoing steps # 100 , # 200 , # 300 , and # 400 , a title screen is displayed on the liquid crystal display  27 . Thereafter, some area of the game map is displayed at the time of starting the game. The player is now ready for capturing the monsters. The procedure then proceeds to a subsequent step # 500 . 
     In step # 500 , a Pokemon appearance processing sub-routine is executed. In this step, the direction switch  22   a  is operated, to capture a monster, the player character (or the player object) is moved to a probable location on the game map where is hiding for capturing the monster. Since the monster does not always appear every time the player object is moved, the player must stroll to various locations on the game map. The procedure then proceeds to a subsequent step # 600 . 
     In step # 600 , a lottery processing sub-routine is executed. In this step, processing is performed for checking winning numbers of a lottery against each of the player IDs assigned to the Pokemons obtained by the player. Herein, the player wins the lottery if any of the player IDs matches the winning numbers. Thereafter, the processing proceeds to a subsequent step # 700 . 
     In step # 700 , a communication processing sub-routine is executed. In this step, in order to exchange the obtained monsters with a friend, or start a battle with the monster obtained by the friend, the game machine  200  owned by the player and the game machine owned by the friend are connected to communicate with each other. The procedure then proceeds to the player object processing sub-routine of the foregoing step # 200 . The processing in the foregoing steps # 200  to # 700  is repeated until the player switches off the image-display game machine GBP to terminate the game. 
     Referring now to FIG. 8, a description is made of the detailed operation in the lottery processing sub-routine of the foregoing step # 600 . In the monster appearance processing of step # 500 , when no monster appeared at the place where the player object was moved to, it is determined in step S 1  of the sub-routine whether or not the user object is in a lottery place on the game map shown in FIG.  4 . If the answer no, the processing in step # 600  is terminated, after which the procedure proceeds to the step # 700 . On the other hand, if the answer is yes, the processing proceeds to a subsequent step S 2 . 
     It is determined in step S 2  whether or not the current date Dcrrnt is different from a lot-drawing date Ddrwn registered in a later described step S 15 , based the time measured by the clock  14 . If the lot-drawing data Ddrwn and the current date Dcrrnt are the same, that is, if the player object enters the lottery place more than once a day, it is determined that the answer is no. The processing in step # 600  is therefor terminated, after which the procedure proceeds to step # 700 . On the other hand, if the lot-drawing date Ddrwn and the current date Dcrrnt differs from each other, that is, if the player object enters the lottery place for the first time in the day, the procedure proceeds to a subsequent step S 3 . 
     It is determined in step S 3  whether or not the date on which the player object is determined to be in the lottery place in step S 1  is Friday on the basis of the time measured by the clock  14 . In the present exemplary embodiment, it is defined that a lot drawing is performed every Friday. Accordingly, it is determined in this step whether or not the day of the week is Friday. The lot-drawing date may be an arbitrary day of the week including Friday or may be an arbitrary day in the month. If the answer is yes, the procedure proceeds to step S 7 . 
     As a result of the processing in the foregoing steps S 2  and S 3 , the lot drawing is set to be performed only once every Friday. However, the lot drawing may be performed any desired number of times a day by providing a counter for counting the number of times of lot drawing, as required, and by allowing the lot drawing only when the counter value is within the desired value. 
     In step S 7 , a first random number Ro 1  for determining the first prize in the lottery is generated. The procedure then proceeds to a subsequent step S 9 . 
     In step S 9 , a second random number Ro 2  for determining the second prize in the lottery is generated. The procedure then proceeds to a subsequent step S 11 . 
     In step S 11 , a third random number Ro 3  for determining the third prize in the lottery is generated. The procedure then proceeds to the subsequent step S 15 . The first, second, and third random numbers Ro 1 , Ro 2 , and Ro 3  which are generated in steps S 7 , S 9 , and S 11  correspond to the player IDs, shown in FIG. 3, of the monsters. Specifically, in the present embodiment, the three types of player IDs are respectively selected by the random numbers Ro 1 , Ro 2 , and Ro 3 , and are respectively taken as first, second, and third prize winning numbers Ro in the lottery. Accordingly, the more monsters a player has obtained from the other players, the greater the player&#39;s chances of winning the lottery. 
     In step S 15 , the current date indicated by the time measured by the clock  14  is set as the above-mentioned lot-drawing date Ddrwn. The procedure then proceeds to a subsequent step S 19 . 
     As a result of the processing in the step, when the player object enters the lottery place totally for the first time, the lot-drawing date Ddrwn has not been set yet. In such case, in step S 2 , it is determined that the answer is yes, and the procedure proceeds to step S 3 . When the player object enters the lottery place for the first time in the day, it is also determined that the answer is yes in step S 2 . 
     Note that, if it is determined in step S 3  that the answer in no, that is, if the date is not Friday, the processing in step # 600  is terminated, and the procedure proceeds to step # 700 . 
     In step S 19 , the first, second, and third prize winning numbers which are determined in steps S 7 , S 9 , and S 11  are displayed for the player on the liquid crystal display  27 . The procedure then proceeds to a subsequent step S 23 . 
     In step S 23 , the value of a natural number n representing arbitrary one of the Pokemon records R 1  to RN which are recorded in the obtained Pokemon data region DAamP shown in FIG. 3 is set to 1. The procedure then proceeds to a subsequent step S 25 . 
     It is determined in step S 25  whether or not the first random number Ro 1  is the same as the player ID (Rn). That is, it is determined whether the value of the player ID which is recorded in the field I 7  of the record Rn (in this case, N=1) in the obtained Pokemon data region DAamP is the same as the first random number Ro 1  representing the first prize which has been determined in step S 7 . If the answer is no, that is, if the player ID assigned to the first Pokemon obtained by the player does not win the first prize, the procedure proceeds to a subsequent step S 27 . 
     It is determined in step S 27  whether or not n is N which is the maximum number of the records R. If the answer is no, that is, if winning in the lottery has not yet been checked with respect to all Pokemons obtained by the player, the procedure proceeds to step S 29 . 
     In step S 29 , n is incremented by one and the procedure returns to step S 25 . The processing in steps S 25 , S 27 , and S 29  is thus repeated until winning of the first prize is checked with respect to all Pokemons which are obtained by the player. If it is determined in step S 25  that the player wins the first prize, the procedure proceeds to step S 31 . 
     If the answer is yes in step S 27 , that is, if the winning of the first prize is checked with respect to all Pokemons which are obtained by the player, the procedure proceeds to a subsequent step S 35 . 
     Processing in steps S 33 , S 35 , S 37 , S 39 , and S 41  correspond to the foregoing steps S 23 , S 25 , S 27 , S 29  and S 31 , respectively. The winning of the second prize is thus checked with respect to all Pokemons which are obtained by the player. After winning is checked for all Pokemons, the procedure proceeds to a subsequent step S 43 . 
     Processing in steps S 43 , S 45 , S 47 , S 49 , and S 51  correspond to the foregoing steps S 23 , S 25 , S 29  and S 31 , respectively. The winning of the third prize is thus checked with respect to all Pokemons which are obtained by the player. After winning is checked for all Pokemons, the procedure proceeds to a subsequent step S 55 . 
     In step S 55 , lottery blank processing is performed. The processing in the lottery processing subroutine then ends. 
     The lottery processing subroutine also ends if winning processing is performed in any one of steps S 31 , S 41 , and S 51 . 
     FIG. 10 is a flow chart showing the operation in the communication processing sub-routine of step # 700 . As shown in FIG. 10, after a game machine  200  owned by a first user and a game machine owned by another are connected to communicate with each other, two sequences of parallel processing operations occur in the respective game machines as indicated in FIG.  10 . Thus, as shown in FIG. 10, after checks are made with respect to the exchange place, processing operations relating to Pokemon selection, communication preparation, Pokemon transmission to the other machine, Pokemon receiving from the other machine, and property data are performed in each machine. 
     Although in the above-mentioned embodiment, a case where the portable game machine and the game cartridge used therefor are described as an example of the image-display game machine, a video game machine connected to a television receiver may serve as an alternative. An information storage medium in the case may be a game cartridge, an optical storage medium such as a CD-ROM or a DVD, a magnetic disk, or the like. 
     While the invention has been described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is understood that numerous other modifications and variations can be devised without departing from the scope of the invention.