The article notes ongoing illegal work problems among foreign workers in Japan and outlines visa categories and the growing Vietnamese community. It reports on Tokyo's Vietnamese Workers Day, where about 400 youths took part in a law-quiz event to deepen understanding of regulations, and quotes Vietnamese Ambassador Pham Quang Hieu urging compliance with Japanese law, while highlighting NGO efforts to support workers. It also cites a case of a Vietnamese woman who entered on a technical visa and was arrested for unauthorized work, with her husband expressing concern about her health.