1 . A computer-implemented method comprising:
generating a plurality of playing cards, each playing card having a unique identifying code and one or more associated attributes; distributing the plurality of playing cards to a plurality of players, each player receiving at least one playing card; receiving electronic information relating to a playing card's unique identifying code from one or more of the players; and maintaining an online data registry relating to each playing card for which electronic information has been received.
2 . The method of claim 1 in which maintaining the data registry comprises tracking the one or more attributes associated with each playing card.
3 . The method of claim 2 further comprising updating the data registry by modifying one or more attributes associated with a playing card in response to receiving information indicating a change in status of the playing card.
4 . The method of claim 2 wherein the one or more attributes include a current owner of the playing card.
5 . The method of claim 2 wherein the one or more attributes include a value of the playing card.
6 . The method of claim 5 wherein the value of a playing card comprises a strategic value or a monetary value or both.
7 . The method of claim 1 wherein one or more of the playing cards are physical entities and wherein distribution is achieved via physical distribution channels.
8 . The method of claim 1 wherein one or more of the playing cards are virtual entities and wherein distribution is achieved via electronic distribution channels.
9 . The method of claim 1 further comprising maintaining a knowledge database containing complementary information relating to subject matters of one or more of the playing cards.
10 . A playing card system comprising:
a plurality of playing cards, each playing card having indicia of subject matter, and a machine readable code uniquely identifying the playing card from among all other playing cards having identical indicia of subject matter; and an online data registry configured to track information about each uniquely identified playing card.
11 . The system of claim 10 wherein the online data registry is configured to track one or more attributes of each uniquely identified playing card.
12 . The system of claim 11 wherein the one or more attributes include a current owner of the playing card.
13 . The system of claim 11 wherein the one or more attributes include a value of the playing card.
14 . The system of claim 13 wherein the value of a playing card includes a strategic value or a monetary value or both.
15 . The system of claim 10 further comprising rules of play that encompass instructions on execution of each player's turn and a predetermined way that cards may be used or played, a quantity of cards permitted to each player at the start of the game, and a hand of cards available to each player.
16 . The system of claim 15 wherein the rules of play further comprise a method of playing a game including one or more of the following:
assembling an individual collection of cards from a totality of cards and offer to the public by purchasing cards or acquiring from players or both; using a unique identifying number or insignia on each card to register each card to a respective player in the online data registry and thereby identify that card as being part of the player's collection; constructing a playing collection of cards from a player's total pool of cards, the constructing being achieve by the player selecting individual cards with which the player elects to play in that game; increasing options for each selection of a playing collection of a predetermined number of cards by the player acquiring additional cards with new or additional attributes and adding these acquired additional cards to the player's registered collection of cards; and applying any attributes attached to a particular card in order to secure a strategic advantage in accordance with rules of the game.
CROSS REFERENCE TO RELATED APPLICATION
 This application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/895,389, filed on Mar. 16, 2007, and entitled “Game of Strategy Using Trading Cards or Other Token”, the entire disclosure of which is incorporated herein by reference.
 The following disclosure pertains generally to games that combine chance and strategy and, more particularly, to a novel method by which Trading Cards (equivalently, playing cards) which are uniquely identified by means of a code or other device, can be registered on a database or registry and thereby validated as being “active” and able to be used in the Internet or connected network form of a strategy game or to track each Card within a player's or collector's collection and the attributes connected to that Card regardless of changes in ownership of that Card for any reason.
 Trading Cards are a well-known form of commercial collectable product, typically resembling conventional playing cards but featuring famous, historical or notorious persons or objects such as sports persons, motor vehicles, famous race horses and other historical or public figures or objects or events rather than denominations or suits.
 Enthusiasts typically collect and trade Cards to make up “sets” being all or substantially all the Cards identified as being in a particular series. Such Cards are typically sold through retail game stores and other specialty outlets and traded between enthusiasts. Enthusiasts typically collect, collate and trade Cards in order to acquire Cards not already in their collection or which they wish to duplicate for strategic purposes where the collector is also a player of games which use those Cards.
 Trading Cards which are capable of being registered and thereby used to play strategy games via the Internet or connected network can be created and made available to enthusiasts. Each Card can depict a particular subject, narrative about that subject and/or bear a unique identifying code or mark which is capable of being scanned and thereby registered on a central database or registry. Trading Cards may be single sided or double sided and may bear a mix of graphical information and textual information.
 One feature of such Cards may be the inclusion of a machine-readable unique code on each Card, enabling each Card to be identified by that code rather than the graphical or textual information on it.
 A form of Trading Card game which can include strategy in addition to chance, can use Trading Cards which, if used in accordance with the rules of that game, would enable a player to form a unique combination of components that can compete against the combinations of other players. These Cards may be played physically, or as “virtual” Cards in an internet or connected network game.
 Trading cards can also be used to represent certain persons and their attributes; by way of example, historical military leaders or figures generally credited with particular acumen or skill in conducting battles. These battles can have happened at any time whether recently or many hundreds of years ago or may re-enact historically recorded battles using different “armies” or introduce other variables to the attributes of the armies' commanders and the strategies adopted by them in the actual battle being re-enacted.
 Players can assemble sets of these Cards: a set which would typically include a Card of a particular military leader and other cards depicting subordinates and other cards depicting historically appropriate weapons, soldiers and armaments for that particular military leader's army or historical period. By way of example, a player could assemble a Roman army headed by a nominated Roman commander. Another player could assemble an army from another historical time such as Napoleon's army.
 By registering their cards, these players could pitch their respective armies against each other, notwithstanding the historical difference between the armies. The respective players' collection of Cards—which makes up their army for the particular game—represents a variety of attributes, things and people and each Card's unique attributes.
 By having each card bear a unique identifying code or mark, that particular card can be registered as belonging to a particular player and no other and can be recognized as such in a computer based game.
 By maintaining a central registry of trading cards and each card's owner, the registry may be updated at any time should a particular trading card be transferred to another player or new attributes acquired in the course of game play. In the case of a traded or transferred Card, the acquiring player can scan the card and thereby amend the central registry to show the change of ownership and also transfer the attached attributes as recorded in the central database or registry. Should that player in time dispose of a trading card, any attributes acquired or lost during that player's ownership, will in turn be passed on to the next acquiring player or collector and so on.
 Trading cards have varying monetary values depending upon the popularity of the subject matter depicted on the card, the relative scarcity of the particular card or its relative value in a game where various collectable cards have certain pre-defined attributes in the game's rules. By uniquely identifying each Card, attaching attributes to particular Cards and thereby differentiating Cards which otherwise depict the same image or subject matter, the value of a particular Trading Card can be increased or decreased: this enhances the trading of the physical Cards as well as affecting any particular Card's value to game players in the Internet version of a game.
 In one form, a game using such cards may include two or more players. The game components include rules of play and the various game elements; by way of example, Trading Cards. The Trading Cards are freely tradable among the players so that each player obtains and constructs their own set of game elements and thereby competes against the sets of game elements assembled by other players.
 The game can also include a method for tracking each Trading Card's variable attributes and ownership so that players can know any particular Card's attributes and strategic value in a game thereby affecting that Card's monetary value as a collectable and also its strategic value as a game element.
 In accordance with one aspect of the present invention, the game elements comprise physical Cards. Each Card depicts a particular subject matter and also bears a unique code, meaning that otherwise identical Cards are in fact not identical because each is identified by its unique code which attaches that Card to the related data in the database or registry. That data includes ownership and attribute details which form a part of that Card.
 In an implementation, the game includes rules of play which determine the way each Card may be played and the consequences so as to result in a winner of the game through strategic use of Cards to “attack” and “defend” or “counter-attack” to simulate the strategies of physical battles and the likely consequences of those strategies and related game elements being utilized in the particular circumstances of that game.
 As an example, a player with a collection of Cards depicting, by way of example, a Roman army, may play a game against another player who has, by way of example, a collection of Cards depicting a Chinese army, notwithstanding that this would not have been possible in the real world as they were not contemporaneous. Similarly, a player who has an army made up of imaginary, fictional or fantasy characters or derived from scenarios such as science fiction or fantasy fiction, can stage battles with other players who have collections of historically based armies.
 Ranges of collectable Trading Cards within a common motif or theme can be made available to players and enthusiasts through retail and other distribution channels. Players can build their collections by purchase, conquest or trade with other players and collectors.
 Players register themselves on the database or registry and acquire a unique code which the player may choose to keep secret. Quoting that code may be a prerequisite for access to the database or registry relating to the player and to the Cards that player posses or acquires whether by way of purchase, conquest, trade or otherwise.
 When a Card changes ownership or attributes, the database or registry may be amended thus: the player holding the Card scans it with an appropriate electronic device such as digital camera, mobile phone camera, bar-code scanner or other technological device whereby the unique code is “read” and that data transmitted to the database or registry. That data is added to the existing data relating to the Card with that unique code and thereby becomes part of that Card albeit in the form of data stored in a remote computer system. Entry of data, amendment of data and access to the data generally is controlled by each player having a password or code which identifies that player uniquely.
 In another implementation, a player may, by selecting and playing Cards in a particular sequence, choose appropriate game assets to attack the other player's army or fend off the attack of another player. The choice of Cards, the sequence in which they are deployed are player determined. The range of Cards available to be played in that game at that particular time may be determined by luck, if the choice of Cards for each player is determined by random selection instead of conscious choice, or by the player pre-selecting the range of game assets to be deployed in that game based on that player's assessment of the battle scenario.
 In another implementation, players who win more games than they lose can add attributes to the Cards they have collected and attach those attributes by amending the relevant Card's database or registry entry. This is achieved by scanning the Card by use of a digital camera or other appropriate device.
 The disclosed cards and method of use provide a game that can be played in many game formats, including hand-holdable physical Cards, virtual Cards, other physical objects which are not physically comparable to normal playing cards but which are capable of carrying an image and associated information and the unique code, electronic games, computer software, interactive networks, board games, and the like.
 Typically the game is fast-paced and a high level of strategy and knowledge will reward a player, but the game is capable of being adapted to permit players of all levels of skill and ability to participate and for individual players to add value to Cards in their collection by being successful in playing against other players and then recording those attributes on the database or registry.
 Attributes may also be acquired or “earned” by participating in and contributing to a knowledge database created by contributions by players via connection to the Internet. This database would typically contain historically accurate or useful information about battles, commanders and strategies which would be of use to other players. Players who contribute to the database could be rewarded by being awarded new or unusual attributes to add to their choice of Card or game asset, thereby increasing that Card or game asset's strategic and monetary value.
 The game, through the use of a unique code associated to each Card distributed, combined with a central database or registry in which each Card's attributes and ownership are recorded, gives a game player the unique ability to modify the attributes of a Card notwithstanding that it depicts the same image or property as similar looking Cards held by other players.
 It further gives the player the ability to adapt their game components, enabling them to pitting players against each other in a battle of strategic skill. The game further includes the unique feature of components that have a tradable and a collectable status above and beyond mere relative scarcity in the market. In other words, certain Cards can become more valuable as they acquire more attributes in their attached central database or registry and thus become more useful in game play and therefore more valuable to players generally, thus encouraging players to trade and collect game components.
 Furthermore, the game permits players to acquire their own collection of game assets and to enhance their attributes as registered in the database or registry in an effort to obtain competitive advantage as permitted by the game's rules and the provisions and availability of each component, as well as the player's skill in choosing game components prior to and during play.
 In one implementation, a computer-implemented method includes generating a plurality of playing cards, each playing card having a unique identifying code and one or more attributes; distributing the plurality of playing cards to a plurality of players, each player receiving at least one playing card; receiving electronic information relating to a playing card's unique identifying code from one or more of the players; and maintaining an online data registry relating to each trading card for which electronic information has been received. Maintaining the data registry may include tracking the one or more attributes (e.g., monetary value, strategic value, current owner) associated with each playing card and updating the data registry accordingly. The data registry may be updated by modifying one or more attributes associated with a playing card in response to receiving information indicating a change in status of the card.
 The playing cards may be physical entities in which case distribution is achieved via physical distribution channels. Alternatively, or in addition, the playing cards may be virtual entities in which case distribution is achieved via electronic distribution channels.
 In addition, a knowledge database containing complementary information relating to subject matters of one or more of the playing cards may be maintained and used to supplement either game play or information in the data registry or both.
 In another implementation, a playing card system includes a plurality of playing cards, each playing card having indicia of subject matter, and a machine readable code uniquely identifying the playing card from among all other playing cards having identical indicia of subject matter; and an online data registry configured to track information about each uniquely identified playing card.
 The online data registry may be configured to track one or more attributes of each uniquely identified playing card. The one or more attributes include a current owner of the playing card and/or a value of the playing card, such as a strategic value or a monetary value or both.
 The playing card system may further include rules of play that encompass instructions on execution of each player's turn and a predetermined way that cards may be used or played, a quantity of cards permitted to each player at the start of the game, and a hand of cards available to each player.
 The rules of play may further specify a method of playing a game including one or more of the following: assembling an individual collection of cards from a totality of cards and offer to the public by purchasing cards or acquiring from players or both; using a unique identifying number or insignia on each card to register each card to a respective player in the online data registry and thereby identify that card as being part of the player's collection; constructing a playing collection of cards from a player's total pool of cards, the constructing being achieve by the player selecting individual cards with which the player elects to play in that game; increasing options for each selection of a playing collection of a predetermined number of cards by the player acquiring additional cards with new or additional attributes and adding these acquired additional cards to the player's registered collection of cards; and applying any attributes attached to a particular card in order to secure a strategic advantage in accordance with rules of the game.
 The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF THE DRAWINGS
 FIG. 1 shows an example of a trading card in the form of a playing card bearing a form of unique code that identifies that Card uniquely amongst the many Cards bearing a similar image or subject matter held by players and collectors generally.
 FIG. 2 . is a flow chart of a method for tracking trading card attributes.
 The present disclosure pertains to a method by which trading cards, which may be acquired by any suitable means, may be scanned and registered by the relevant player in order to use that card to play a game for two or more players wherein the players may apply the attributes or characters embodied in any registered trading card, in a game played on the Internet or other connected network.
 Each player collects and assembles a variety of cards which represent a chosen commander and the components of that commander's “army” to wage a virtual war with the other players, which involves careful pre-game selection of cards so as to create a particular combination of attributes and then plays against other players each of whom has their own
 FIG. 1 shows an example of a trading card in the form of a playing card 100 bearing a form of unique code 102 that identifies that card 100 uniquely among one or more other cards bearing a similar or identical image or subject matter held by players and collectors generally. In other words, two or more collectors could have versions of this card 100 that appear otherwise identical but are uniquely identifiable (and trackable in a database) by virtue of their respective, and different, unique codes 102 . In this example, the card 100 includes indicia of subject matter 106 , such as shown an image of a military commander along with related information 104 (which might instead be included as part of the indicia of subject matter 106 ). Although the unique code 102 shown in this example is a standard bar code, virtually any other type of suitable machine readable code (e.g., two-dimensional matrix code or the like) could be used instead.
 An owner of the card 100 can register it with a central database, for example, by scanning the unique code 102 (e.g., using a digital scanner, digital camera, cell phone camera or other suitable optical capture mechanism) and then uploading (e.g., online using an Internet web form, via text or SMS message or other cell phone data transmission, via email, or the like) the scanned image (and/or information descriptive of the scanned unique code 102 ) to a central database or other registry or data repository. Each unique card can have a set of one or more default attributes which typically would be the same as or similar to the default attributes of other cards bearing the same or similar personages or other subject matter. Subsequently, through game play or otherwise (e.g., card trading, payment of money, other user input or actions, passage of time, external events, etc.) attributes of each individual card 100 can be modified and tracked via the central database. Consequently, each card becomes unique unto itself over time and thus will attain certain values (monetary, strategic or otherwise) and/or other attributes that differ from other cards bearing the same personages or subject matter. In addition, changes in ownership of a card can be tracked using the database.
 FIG. 2 is a flow chart showing a method of tracking attributes of individual playing cards. At 200 , a plurality of playing cards is generated. Each playing card has a unique identifying code (e.g., bar code) and one or more associated attributes (e.g., monetary or strategic value, current owner). The cards can either be real, physical entities (e.g., standard playing cards made of cardboard or plastic tokens) or virtual entities (e.g., electronic objects distributed through electronic channels such as telecommunications or data networks). In either case, the cards are distributed via an appropriate channel ( 202 ).
 A player who receives such a card may scan its bar code or other unique code and upload the information to a central, online registry (e.g., an online database or other data repository). This information is received at the central registry ( 204 ) and used to maintain in the online data registry information about each card for which electronic information was received ( 206 ). Upon detecting (e.g., based on newly uploaded information from a player) a change in a card's status (e.g., change in attribute value) at 208 , the data registry is updated by modifying one or more attributes for that card ( 210 ).
 The present game is directed not only to the method of registering the trading cards, but also to the method of playing the game and the means of generating revenue from same for the party hosting the Internet version of the game and creating Trading Cards capable of being utilized in this way.
 The method of play can be expanded to include a winner taking one or more of the loser's Cards at the end of a game or game set or tournament. For instance, the complete collection of cards in any complete set may number hundreds of individual Cards, each with a unique code, thus making them uncommon. Some Cards will have restricted publication and distribution, making those Cards rare. The basic nature of each Card defines the limits to the additional attributes that that kind of Card may acquire. For example, the rules of the relevant game could provide that a General in a war-game would have a wider and different range of attributes to a Sergeant or a Private in that game.
 Other cards will have virtually unlimited distribution, rendering them common. Players obtain cards by purchasing them at retail outlets, trading them with other players, or winning them as ante or prizes at games and tournaments.
 In one implementation, a party may act as “host” of the database or registry and maintain that data which player access via the use of their unique code, through the Internet or other connected network. That registry host may or may not also control which Trading Cards which may be registered on the database or registry.
 That party may or may not also conduct the means by which these games may be conducted by Internet or other connected network. This may involve a charge or cost to each player for (by way of example only):
the right to access the database or registry the right register as a Card owner and to secure a unique player code the right to play games on the hosts service the right to access, use or consume any other goods or services the host wishes to provide to players and enthusiasts.
 It is to be understood that the game components or assets can take different forms. For instance, in one version of the game, the components are hand-held Cards similar in physical specification to a regular playing card. In another version of the game, Cards are plastic tokens or shapes bearing graphical and textual data and that Card's unique code. In another form of the game, the players interact with each other via a computer network, with the game components visually displayed on the monitor. Hence, the foregoing game, including the tradable aspects thereof, are not to be limited to the embodiments described herein.
 In another version of the game, each player acquires digital versions or representations of Cards (“Virtual Cards”), thereby enabling players to play other players by using their collection of Virtual Cards on a computer or other electronic device. Provided each such Virtual Card is registered to the relevant player. Once registered, each player may play against other players, alter the database or registry relating to that Card and trade the Card with the attributes attached, thereby augmenting its strategic and monetary value.
 This also applies to the method of playing the game. In one form, the game involves each player acquiring Cards and utilizing them and a combination of them to play the relevant game; for example to engage with a strategy game such as battle, with any other player or multiple players subject to the applicable rules of the game.
 Furthermore, play can be accomplished between a player and an artificial intelligence or simulated opponent such as a computer, or expanded to permit multiple players to play simultaneously in accordance with the game's rules. While the fundamental rules of play apply in multi-player and tournament games, modifications can be made as necessary to accommodate the needs of the game and the wishes and intentions of the applicable players or the hosting party.
 Another potential feature is the ability to modify the strategic and commercial value of any Card or game component by adapting and altering the Card's database and attributes. This facility also enables the host to generate revenue by charging players for additional attributes, auctioning attributes, offering attributes as prizes and enabling players to participate in activities whereby the players can create, nominate or request new or amended attributes in order to increase a Card's strategic or monetary value.
 The nature of Trading Cards which both carry information on their face as well as having a range of attributes accessible to the owner via authorized access to the database or registry, gives them a collectible nature. This encourages players to trade for more powerful Cards and to complete a set of Cards for game playing as well as collecting purposes.
 However, some players are reluctant to play with collectible cards for fear of damage or loss. Hence, an unlimited version of the game can be made available strictly for playing purposes.
 In accordance with an implementation, the game is played by two players in which Cards in each player's playing collection represent soldiers and weapons at a player's disposal. In playing the game, each player would wage a campaign using the soldiers and weapons chosen or randomly selected to be in that player's playing collection, against an opponent's playing collection in a battle, with the winner taking one random Card to keep from the loser's playing collection. Over time, each player's playing collection will fluctuate in size and individual Cards may be won and ownership registered by amending the database or registry. A player may endeavor to compensate for losses or weaknesses by winning Cards through other games and bartering for Cards between games with other players.
 The methods described here can be used on existing and readily available electronic devices, such as computers, mobile telephones, video games, electronic games and on interactive networks utilizing computer software and text. Such electronic devices can visually display the Cards and enable players to select the cards and execute turns as described hereinabove. Commercially available electronic communication devices can also be provided to enable players to communicate with each other over long distances.
 Another version of the game can be played using a playing board. This board has pathways on it divided into segments or territories in which the players move in accordance with the rules of the relevant game.
 A number of implementations have been described. These and other implementations are within the scope of the following claims.