Abstract: In concealment sheets for information recording paper, adhered to the same, such as facsimile recording paper or the like, for the purpose of concealing information displayed on the information recording paper, a transparent protective layer for protecting the information displayed on the information recording paper is provided on at least one surface of a sheet base, and the protective layer is peeled away from the sheet base and then can be moved to the side of the information recording paper after it is adhered to the information recording paper. With the above construction, deterioration of the information, such as the deterioration of the characters displayed on the facsimile recording paper or the like, can be prevented. The paper can be prevented from curling by stiffening the facsimile recording paper. What is more, falsification of displayed information can be prevented.

Abstract: A communication medium such as a postcard in which surfaces on which information, e.g., communication sentences is shown are bonded by heating with a synthetic resin film or the like interposed therebetween to send the information while concealing the information and other printed contents, a method of manufacturing this communication medium, and a communication medium intermediate sheet including a synthetic resin film or the like interlaid in the postcard. The synthetic resin film interlaid in the communication medium can be torn apart. The provision of such a film capable of being torn facilitates the operation of cutting off communication medium units of the postcard size and enables the receiver to easily dispose of the communication medium by tearing the same into pieces after unsealing the communication medium and reading the secret information.

Abstract: A confidential sheet in the form of a sealed letter, postcard or the like and having a sheet body bearing the information to be concealed on one surface thereof, the confidential sheet being formed in a lapped state by folding the sheet body in at least two with the information bearing surface inside. The body comprises means for preventing the information from being seen through from outside.A paper for preparing the confidential sheet has a body bearing information on one side thereof and comprising means for preventing the information from being seen through the other side thereof.A continuous form for successively making a plurality of sealed letters, postcards or like confidential sheets bearing concealable information, the body of the form bearing the information on one side thereof and comprising means for preventing the information from being seen through the other side thereof.

Abstract: The invention concerns a two-way communication medium in the form of double post card or the like which enables easy communication of information in secret during both forward mailing and reply mailing, and which can be opened with little or no trouble for reading of the information.Sheet portions of the two way communication medium body are folded one over another with the information written surface or surfaces placed inside. A releasably adherent insertion sheet is interposed between the superposed sheets. The insertion sheet provides good adhesion contact between its surfaces and individual sheet portion surfaces.

Abstract: The invention relates to a two-way communication sheet in the form of double post card, double letter sheet, or the like for use in communicating under cover written information and the like which should be protected from disclosure. The two-way communication sheet is so arranged that a sheet portion on which information is written is bonded to other sheet portion or portions when the communication sheet is initially forwarded as well as when it is sent in reply, so that the information is prevented from being exposed outside. The communication sheet is quite novel in that it enables information to be communicated in secret condition.