Whatever is given to a devotee of Śiva with sincere faith accords Śiva’s region. Or the devotee can repeat the Praṇava mantra ten thousand times every day.
Repetition of Om (Praṇava mantra) a thousand times at dawn and at dusk is known to be according Śiva’s region. At the time of the repeated utterance (Japa) of the mantra, (Om) ending with “M” purifies the mind.
At the time of Samādhi (meditation) the repetition of Oṃkāra must be mental. Muttering of it in low voice can be practised at all times. The same with Bindu (dot) and Nāda (sound) is also of the same efficacy.
Or the devotee can with due reverence repeat the five-syllabled mantra ten thousand times every day or a thousand times at dawn and at dusk. It accords the region of Śiva.
Repetition of the five-syllabled mantra (Namaśśivāya) by a brahmin is specially efficacious with the Om (Praṇava) prefixed. A mantra must be received from a preceptor with proper initiation for the acquisition of the desired fruit.