Vajradhara (Sanskrit: वज्रधर; Tibetan: རྡོ་རྗེ་འཆང། rdo rje 'chang (Dorje Chang); ; Javanese: Kabajradharan; Japanese: 持金剛仏; English: Diamond-holder; Vietnamese: Kim Cang Tổng Trì) is the ultimate primordial Buddha, or Adi-Buddha, according to the Sakya, Gelug and Kagyu schools of Tibetan Buddhism. It is also a name of Indra, because "Vajra" means diamond, as well as the thunderbolt, or anything hard more generally.
In the evolution of Indian Buddhism, Buddha Vajradhara gradually displaced Samantabhadra, who is the 'Primordial Buddha' in the Nyingma, or 'Ancient School.' However, the two are metaphysically equivalent. Achieving the 'state of Vajradhara' is synonymous with complete realisation.
According to the Kagyu lineage, Buddhā Vajradhara is the primordial Buddha, the Dharmakaya Buddha. He is depicted as dark blue in color, expressing the quintessence of buddhahood itself and representing the essence of the historical Buddha's realization of enlightenment.
As such, Buddha Vajradhara is thought to be the supreme essence of all (male) Buddhas (his name means "Ruler of the Vajra Beings"); It is the Tantric form of Sakyamuni which is called Vajradhara. Tantras are texts specific to Tantrism and are believed to have been originally taught by the Tantric form of Sakyamuni called Buddha Vajradhara. He is an expression of Buddhahood itself in both single and yabyum form. Buddha Vajradhara is considered to be the prime Buddha of the Father tantras (tib. pha-rgyud) such as Guhyasamaja, Yamantaka, and so on
From the primordial Buddha Vajradhara/Samantabhadra Buddha /Dorje Chang were manifested the Five Wisdom Buddhas (Dhyani Buddhas):
Akshobhya
Amoghasiddhi
Amitabha
Ratnasambhava
Vairocana
Buddha Vajradhara and the Wisdom Buddhas are often subjects of mandala.
Buddha Vajradhara and Samantabhadra Buddha are cognate deities in Tibetan Buddhist cosmology with different names, attributes, appearances and iconography.