Dharmachakra in Sanskrit means the 'Wheel of Dharma'. This mudra symbolizes one of the most important moments in the life of Buddha, the occasion when he preached to his companions the first sermon after his Enlightenment in the Deer Park at Sarnath. It thus denotes the setting into motion of the Wheel of the teaching of the Dharma.
In this mudra the thumb and index finger of both hands touch at their tips to form a circle. This circle represents the Wheel of Dharma, or in metaphysical terms, the union of method and wisdom.
The three remaining fingers of the two hands remain extended. These fingers are themselves rich in symbolic significance:
The three extended fingers of the right hand represent the three vehicles of the Buddha's teachings, namely:

• The middle finger represents the 'hearers' of the teachings
• The ring finger represents the 'solitary realizers'
• The Little finger represents the Mahayana or 'Great Vehicle'.

The three extended fingers of the left hand symbolize the Three Jewels of Buddhism, namely, the Buddha, the Dharma, and the Sangha.
Significantly, in this mudra, the hands are held in front of the heart, symbolizing that these teachings are straight from the Buddha's heart.
This mudra is displayed by the first Dhyani Buddha Vairochana. Each of the five Dhyani Buddhas is associated with a specific human delusion, and it is believed that they help mortal beings in overcoming them. Thus, Vairochana is believed to transform the delusion of ignorance into the wisdom of reality. By displaying the Dharmachakra mudra, he thus helps adepts in bringing about this transition