Japa is not physical but it is mental and is to be raised to a still deeper level. Neither a mere rolling of the beads, or nonstop muttering of the sacred-mantra in the mouth, can by themselves constitute the Japa-Yoga
Japa generally enchants the unwary practitioner into the jungles of the unproductive thought-wanderings. If the student is not diligent enough to detect it and arrest the flow of thoughts (not by force but by awareness and silent and smooth shifting of awareness from the thought to the mantra), it is possible that Japa ends him in a dark ditch of frustration and stupor.
Initially, Japa should not be over practiced, but has to be gradually increased.
Another difficulty is common to ninety percent to Japists, is an irresistible attack of sleep while doing Japa and shamelessly evident tendency to express bad temper soon after the Japa-Sadhana. The seeker should not get annoyed at himself on these symptoms. He should learn to patiently fight these tendencies and win over them.
Sleep comes because a mind in Japa is at rest. Train the mind not to sleep in calm environment within.
Bad temper comes because of 2 reasons- suppression of tendencies and consequent fatigue. Former starts with the Japist’s own annoyance at his own mind wandering here and there during Japa. Some of them even stop the Japa in the middle which is not advisable. One should note that thoughts are technically not coming, but they are going, just let them go and be aware of Japa Mantra. The latter is caused by exhaustion, because, to hold the mind on mantra is a great strain to the beginner and therefore, his mind gets fatigued.
But both can be get rid of by constant disciplined practice. Regularity and sincerity are secrets to success in spirituality. A learner in swimming gets tired after sometime. Later, he swims to relax and remove tiredness.
Profit-motive action is the strongest urge in man in all his strenuous activities. Japa is also polluted by his profit-motive and cannot end in spiritual effulgence of the one doing even if Japa is done sincerely.
Japa with an expectation for success and profit-motive attitude can be get ridden by surrendering ourselves and all our actions to God.
Extracted from “A manual of Self Unfoldment” by Swami Chinmayananda