The Criminal Act is based on the principle of legality and the principle of clarity. The principle of legality that crimes and penalties ought to be specified in the law is the great principle of criminal law. The principle of clarity that criminal statutes and ordinances ought to be specific in order for an ordinary person to be able to know how his/her act is punished is the important principle of criminal law which supports the principle of legality. The Criminal Act prescribes that “an act of publicly alleging facts or false facts” shall be punished. The constitution of criminal defamation ought to be determined based not on whether there is propagation possibility of the alleged facts but rather whether an act of revealing facts per se has publicity. In such a case, publicity, through the analysis of the nature and modality of the act, ought to be determined in consideration of whether the act was revealed to many and unspecified persons, whether many and unspecified persons recognized or could have recognized the facts as an act of alleging facts was done in a public place, etc., and whether the revealed facts can be seen to be disseminated socially and publicly. The theory of propagation possibility is contrary to the principle of legality as it results in the creation of a new constituent element referred to as propagation possibility in addition to publicity, which is a constituent element of criminal defamation. Furthermore, the theory of propagation possibility impedes a function as a conduct regulation of criminal defamation by confounding the principle of clarity and leads a person applying the law to arbitrarily administer criminal laws and ordinances. D. The theory of propagation possibility is a bar to consistent and systematic interpretation on publicity of other crimes, which consider publicity as a constituent element. The distribution, etc. of obscene pictures stipulated in Article 243 of the Criminal Act regards publicity as a constituent element by prescribing “any person who openly displays or shows any obscene pictures, etc.” Supreme Court Decision 73Do409 decided August 21, 1973 does not consider propagation possibility unlike publicity as referred to in criminal defamation by determining that “openly displaying or showing any obscene pictures, etc. is to bring out a state where many and unspecified persons can watch obscene pictures, etc., but a state where a small number of specified persons can watch them does not correspond thereto.”