Everything in nature is conditioned by the fundamental principle expressed in the unity of opposites: yin-yang. The fusion of the male and the female is a creative act and the source of life. Even though Buddha Nature is beyond genders, Buddhist iconography uses sexual polarity to symbolize the Mahayana and Vajrayana concept of the union of principles: female wisdom (Skt. prajna, Tib. sherab) and male compassion (karuna, nyingje) or skilful method (upaya, thab).
The union of wisdom and compassion symbolizes the non-polarized state of bodhicitta (jang chub sem), or the mind of enlightenment, which is represented visually by showing two deities engaged in sexual union. In Tibetan Buddhism such images are known as yab-yum, which literally means father-mother. The Sanskrit term for such union is yuganaddha (union of opposites), which refers to Tibetan term zung jug.
This sexual metaphor is also used to denote the highest stage of Tantric yoga in which there is no duality, no discrimination, and the truth is one, indivisible, and absolute. This state of complete harmony can be expressed as union of method and wisdom (thab she zung jug) or union of bliss and emptiness (de tong zung jug). Another term used in Tantric Buddhism for the union of male and female principles as a supreme path to perfect enlightenment is maithuna.
This Sanskrit term has several meanings – “couple,” “merging,” “union,” “marriage,” “relation,” “sexual intercourse,” “ritual sexual act,” and so on. It is used both in the Buddhist and Hindu Tantric traditions. In the context of the Tantric ritual, maithuna exemplifies the interaction between the male and the female energies.
The purpose of this union is to transform the sexual energy into spiritual power and awaken the dormant potential of the consciousness. This process happens spontaneously and is naturally born (sahaja, lhen kye). This spontaneous union (sahaja maithuna) opens the consciousness to new dimensions beyond conceptual thinking in a state of inner silence.
When the sun and moon embrace each other
And when the sky and earth kiss each other
They perform the sacred ritual of the spontaneous union
Of body, speech and mind.
They pronounce the mantra of male and female paths
In the spontaneous silence of bliss.
Enter into the mandala of great bliss
To attain the accomplishment of natural state
And rest your mind in that great perfection.
This is the state beyond state;
The feelings beyond feelings;
The awareness beyond awareness;
The emptiness beyond emptiness;
The bliss beyond bliss;
The great union of emptiness and bliss.
In that great union bodhicitta descends from the inner sky
And ascends from the inner earth to unite in the heart,
The awakened heart of pure and unconditional love.
In that spontaneous union
The individual self is dissolved in the oneness of great bliss.
In that natural union
The primordial wisdom rises as thousands suns and moons.
In that boundless union
The absolute truth is displayed as a complete circle,
Overcoming life and death.