ཨ་མཐར་ཀློང་དྲུག་ཡིག་འབྲུས་བསྐོར།།
Is a syllable A surrounded by the seed syllables of the sixfold expanse.
Guru Sādhana, Guru Yoga, Tibetan Masters, Jamyang Khyentse Chökyi Lodrö, Indian Masters, Garab Dorje