The Mahayana notion of Buddhism had given birth to the concept of Adi-Buddha. The Lord Supreme was conceived of as possessing five kinds of knowledge. From these five knowledge emerged the five kinds of meditation and the five deities who emerge from these meditations are called the five dhyani Buddhas. These five kinds of knowledge are known as the Five Aspects of Enlightened Awareness, with the corresponding dhyani Buddhas they are the Mirror-like Awareness. They are Aksobhya, the Awareness of Equanimity; Ratnasambhava; the Differentiating Awareness-Amitabha; the Awareness of the Performance of Duty-Amoghasiddhi and the Awareness of Pure Nature-Vairocana.
The dhyani Buddhas are five in number to which a sixth Vajrasattva is sometimes added. The first five are embodiments of the five skandhas and the sixth is the union of these five skandhas.
The dhyani Buddhas are the purified forms of the five evils that beset phenomenal existence namely Wrath, Passion, Envy, Malignity and Delusion. In mystic union with the deity the adept envisages these passions etc as aspects of the one mystic unity. The dhyani Buddhas vary in the colour of their body their mystic hand gestures and their recognition symbols. Each has a definite place in the mandala or in the stupa.
Asokbhya
Asokbhya, the Mirror-like Wisdom reflects the form of all things, the immutable foundation of all beings. Asokbhya`s wisdom sees things exactly as they are, without distortion or interpretation perfectly and objectively. Since he shows all beings in their true nature he is the antidote for wrath which is the predominant evil in the realm of hell. Hence he is called the Buddha of the hellish realm. To depict the immutable character of Asokbhya he is represented in the bhumi-sparsa mudra since earth is the symbol of immutability, deep-rootedness and steadfastness.
Ratnasambhava
Ratnasambhava the jewel born also called Ratnesa/Ratnapati which means the lord and the holder of the Jewel, the Wisdom of Equality highlights compassion for all that lives. Compassion springs from his intuition of equality that is everything is perceived as having the same fundamental nature, which is voidness. He is the antidote for pride, the weakness of the human realm and so he is considered the Buddha of the human realm. The aspect of compassion is iconographically represented by his danamudra touching the ground with his palm turned upward.
Amitabha
Amitabha, the Discriminating Wisdom symbolises direct apprehension or inner vision devoid of logical or conceptual ratiocination. He is portrayed in dhyani mudra. He is the red Buddha, seated in a red lotus throne upheld by two peacocks, since the peacock is believed to derive its brilliant colours of its plumage from the poison of snake on which it feeds and thus is the symbol of purification and transformation. The glowing red body of this Buddha signifies his nature which is active compassion. His discriminating wisdom sees the individual needs of every nature. Compassion is the antidote for passionate craving, the evil that inflicts the realm of hungry ghosts. Hence Amitabha is the Buddha of the realm of the hungry ghosts.
Amoghasiddhi
Amoghadiddhi, the Wisdom of the Performance of Duty symbolises karma-free activity which is devoid of attachment but guided by universal compassion. Wisdom is not only passive insight into the nature of things, but also knowledge of what is to be done for the welfare of all beings. Hence he is presented in abhaya mudra seated on a throne upheld by two strange creatures called Shang-Shang. He is the green Buddha, the Buddha of action. His action is directed for the welfare of others and so he is the antidote for envy, the evil that afflicts the realm of Titans
Vairocana
Vairocana, the Wisdom of Pure nature is the state of cosmic consciousness that transcends the ego-bound individual consciousness. This is expressed through his dharmachakra mudra. He is the white Buddha. He represents the teaching function of the Buddha. He is seated on a white lotus borne by two white lions or dragons. The teaching of Lord Buddha is lion`s roar because all the lesser teachings are silenced by it. He is the Buddha of transcendental wisdom and it is the antidote to the ignorance of the real nature of things. This illusion is the predominant evil that afflicts the realm of the gods; hence Vairocana is the Buddha of the world of devas.
Thus, it can be concluded saying that the contemplation of their shapes and colours, their various emblems and figures help ordinary men to realise the qualities that are present within the individuals. Rather the five dhyani Buddhas are provisional figures and one must go beyond them to the essence they signify.