A debate consists of two acts. One is an insistent act in which some have their own opinions or views on the topics. Another is a contradictory act in which the other argue those are wrong and false. Above all, the insistent and contradictory act aims at persuading people who are involved in the debate. Indeed, the debaters have a goal strategy. This is that they firstly insist on their own opinions with persuasiveness, after that they point out their opponents` unpersuasive insistence. In order to show the opponents` unpersuasiveness, the most effective way is to mention their contents. It is a contradictory strategy that I would like to study. Considering the reasonability of the contents, they are looked into by categorizing as a basis of insistence, insistence content itself and the entailment of insistence in contents. In a way with a basis of insistence, a debater can deny the basis or presupposition of insistence, examining the fact and validity in the basis or presupposition. Regarding insistence itself, a debater can be against the core of the insistence itself or a portion of the proposition of the insistence. Lastly, when it comes to the entailment of insistence, a debater can contradict the implied insistence of the opponents.