ANSWER: One characteristic of an uncontrolled mind is that it gets bored doing the same thing over and over again. Japa is repeatedly chanting the same Mantra. An uncontrolled mind is reluctant to do such monotonous chanting. In spite of this reluctance, the mind should be persuaded again and again to chant the same Mantra. Eventually the mind, unless otherwise occupied, will chant the Mantra on its own without any persuasion. This is a clear indication that the mind has to a considerable extent come under control.