S continued - S3

Four Nails (gzer bzhi) - These are the four nails which control life-breath {srog sdom gzer bzhi} according to Yoga Tantra, namely,

• 1) the nail of unchanging intention {mi 'gyur dgongs pa'i gzer}
• 2) the nail of contemplation on the deity {ting 'dzin lha'i gzer}
• 3) the nail of mantra which is the nucleus {snying po sngags kyi gzer} and
• 4) the nail of activity which is the emanation and absorption of light rays {phro 'du phrin las kyi gzer} [RY]

four nails