Baidu Library said that it is legal not to restrict personal freedom. Closed training is a way for enterprises to train employees, as opposed to open training. Closed training refers to bringing employees together for continuous training activities at a specific time and place, strictly limiting employees' freedom and autonomy, and letting employees devote themselves to training. Usually closed training is conducted in the company's own training center, specially rented venues or resorts, which usually takes several days or weeks.