Māṇḍūkī Śikṣā 20

20

svare jñātvā yathā sthānam hastasya spandanaṃ smṛtam
niṣkṛṣya hastaṃ vinyastaṃ pāṇau dṛṣṭiṃ niveśayet

Having recognized [the tone] in its tone according to its place of articulation, the movement of the hand is prescribed; / having drawn out the hand properly positioned, one should fix the gaze upon the hand.