it has been speculated that the first use of the term was in the c. 7th century "mañjuśrīmūlakalpa", in which it refers to a hand gesture. the term is mentioned with increasing frequency as buddhist tantra developed further, particularly in the yogatantras, where it appears in "tattvasaṁgraha" and the "vajraśekhara-tantra". here it also denotes a hand gesture, now linked to three other hand mudrās—the action ("karma"), pledge ("samaya"), and "dharma" mudrās—but also involves "mantra recitations and visualizations that symbolize and help to effect one’s complete identification with a deity’s divine form or awakening mind (bodhicitta)." in mahāyoga tantras such as the guhyasamāja tantra, it "has multiple meanings, including a contemplation-recitation conducive to the adamantine body, speech, and mind of the tathāgatas; and the object-—emptiness-—through realization of which 'all is accomplished,'" and it is also used as a synonym for awakened mind, which is said to be "primordially unborn, empty, unarisen, nonexistent, devoid of self, naturally luminous, and immaculate like the sky."