Patent ID: 8298079

Claim:
A network system having a server and a user device connected together in a communicable manner to allow a user to manipulate a character in a virtual space on the user device, the server including: a verification image transmission unit that transmits a verification image for verifying a character manipulation by the user to the user device based on a progress state on the user device; and an update unit that updates a situation on the user device based on operation information indicating a content of the character manipulation in the user device to which the verification image has been transmitted, the user device including: a management unit that manages a situation including the progress state; an image display unit that displays the verification image when the verification image is transmitted from the server; an operation information transmission unit that transmits the operation information indicating a content of a character manipulation in a state where the verification image is displayed, the server further including: a properness/improperness judgment unit that judges properness/improperness of a character movement with respect to the verification image based on the operation information transmitted from the device, wherein the update unit of the server updates the situation in such a way as to be advantageous for the character when the properness/improperness judgment unit has judged that the character movement is proper; and, a verification image generation unit that generates a verification image in which a specific image is located at an arbitrary position when a predetermined condition is fulfilled, the verification image transmission unit of the server transmits, to the user device, a verification image which is generated by the verification image generation unit every time a location of the specific image is improper, and the properness/improperness judgment unit of the server judges properness/improperness of a character movement with respect to the specific image located in the verification image to judge whether the specific image is viewed by the user.