Four Chinese students have sued the Tokyo Regional Immigration Bureau for attempting to detain them during a crackdown on illegal workers at an esthetic salon chain. Tokyo immigration bureau officials said they want to detain the four students because they were neglecting their studies and spending most of their time trying to make money. But the students argue their visas allow them to work to pay for their academic fees, and that their studies were never neglected. The lawsuit filed at the Tokyo District Court demands an injunction against the detention order. The four students said they will hold a rally at the Upper House members office building on Thursday to protest the bureau's stance. They will also request the immigration bureau officials in charge of the matter to attend a meeting to explain their decision.