U.S. Pat. No. 6,764,402: Image-Display Game System And Information Storage Medium Used Therefor
Issued July 20, 2004 to Nintendo Co., Ltd.


Nintendo describes the multi-player, portable version of its Pokemon game in this patent. In the pokemon game, each player collects and trains pokemon. When another player is encountered, the pokemon battle each other and the winner captures the loser’s pokemon. Capturing a pokemon includes transferring information about its appearance, strength, etc. to the wining player’s game machine.

Battling other actual players, as opposed to simulated opponents, is encouraged by allowing pokemon captured from another player to have a “virus” that allows them to be more effective in battle. The virus spreads quickly, thus helping a player’s entire collection of pokemon. The patent explains that players whose pokemon have the “virus” will become popular: “The player who luckily captures a virus-infected pokemon … becomes busy with other players’ requests for pokemon data exchange, thereby increasing popularity among other players. As such, the game is useful for cultivating friendship with other players.”

Although the game may bring you new friends, those friends don’t have to stick around once they’re done using you. It is possible to receive information about player and his cadre of Pokemon, and then do virtual battle with him later on. There may be some disadvantages to this approach, however. The properties of the pokemon change with the time of day, and a battle that takes place at night may come out differently than a battle that takes place during the day.

The patent also describes a system for allowing players of different versions of the game to battle each other: Whatever information about a captured pokemon is unavailable from the old version of the game gets made up (assigned randomly) at the time of data transfer. Conversely, data about a pokemon from the new version that cannot be received by the old version is discarded. This ingenious system can also be used to allow users who upgrade to the new version to transfer their old collection of pokemon.

Exemplary Claim:
A method of operating a multiplayer video game system for playing a video game involving characters that may be captured by a player comprising the steps of:

establishing communication between a first player’s video game device and a second player’s video game device;

associating time related data with at least a first video game character that may be captured by a player;

controlling the display of said first video game character based upon said time related data;

receiving by said first player’s video game device identification information identifying said second player; and

storing data in said first player’s video game device relating to said at least one video game character associated with said second player including said time related data.

U.S. Patent No. 6,733,383: Systems and Methods for Simulating Game State Changes Responsive to an Interrupt Condition
U.S. Patent No. 6,261,179: Video Game System and Video Game Memory Medium