There are discriminations in the handling with prostitution and lewd act by law and with gambling and speculative act as basic types of illegal acts against the public moral.
For the discriminations, even then the concepts are not defined in law respectively, it is necessary for law enforcement official at least to differentiate that concepts.
Namely, between prostitution and lewd act, the former should be punished with higher statutory punishment and in general concept, but the latter has a discrimination to be punished at 3 specific types by law. The thing that stands on a point of contact of this discrimination is concept of similar sexual intercourse as a prostitution. If we approve the scope of similar sexual intercourse widely, behavior modes of prostitution will be also widened, but if we approve that narrowly, we should consider the lewd acts. According to the attitude of supreme court that takes a view of sexual satisfaction about the concept of prostitution without any additional legislation, the boundary of similar sexual intercourse become vague and that attitude will hurts the legal stability against the clarity on the principle of "nulla poena sine lege". Therefore it is right to differenciate the concepts on the opinion of insertion. After all, prostitution, as it is called, is the behavior to do a sex or a similar sexual intercourse by insertion receiving or being promised the cost from unspecified persons. On the other hand, lewd act, as it is called, is the behavior to take a sexual satisfaction with stimulation against sexual morality including the apparent description and exposure of sexual act, and direct contact of body except for the prostitution.
Meanwhile, there are discriminations between gambling and speculative act that the former is punished in general concept but the latter is punished in specified types and only business owner is punished in the case of the latter. As a standard of these discriminations, we can say that gambling needs participants except for business owner, but speculative act can be formed only with one participant and business owner. If we enforce the law without these distinguish, it happened that participant in the speculative act can be punished by subjective judgement of law enforcement officier in spite of intention of legislator. After all, gambling is the act that participants over 2 offer the property and are decided by the success or failure of the gain of property each other.
From now on, it is necessary to define the concrete concepts about lewd act and speculative act in the legislation or exemplify their major behaviors. By that, citizens and officiers can avoid the confusion at the application of law.