If the m ind is agitated and the breath uneven, something is bothering you, or reciting the Buddha’s name either aloud or in a low voice is inconvenient, you should just move your lips, practicing silent recitation (Diamond Recitation). With this method, the number of recitations does not matter; the essential condition is that each word, each recitation should come from the mind.
The Diamond method differs from recitation in a low voice in that the lips move but no sound is heard. This method is useful when our sleeping or living quarters are close to someone else’s. In such circumstances, reciting in a loud or a low voice might disturb them. We should then just move our lips and practice Diamond recitation. The number of recitations does not matter as long as the Buddha’s name originates in the Self-Mind, moves the tip of the tongue and produces a sublime sound. Even though the sound is not audible, it reverberates throughout the Dharma realm (cosmos) while remaining part of the current recitation.