A hidden entry system comprises a document having a localized coating of a non-pressure sensitive heat activated autogenous chromogenic composition to provide a latent image which reveals hidden indicia when heated at moderate temperatures. The hidden entry system is especially useful for contests and promotional forms. Quickly striking the chromogenic composition with a fingernail or blunt object converts the latent image to a visible colored image by frictional heat. The chromogenic composition contains a chromogenic compound and a color developer which are non-pressure sensitive and non-reactive at room temperature. The latent image can be provided by an intimate mixture of the chromogenic compound and the developer or alternatively, one component can be printed on a separate layer or coating of the other component.