The ancients said, "When heaven is about to confer a great responsibility on a person, it will first frustrate his will, tire his muscles and bones, and make him hungry." This is probably the greatest insight. The military training this time was also the toughest, with daily repetitions of basic movements such as standing at attention, resting at ease, squatting, swinging arms, and marching. These actions that usually seem very simple are now not so easy to perform. The drillmaster has very strict requirements for the accuracy of the movements and also has high expectations for the students.