One of five common mudras or sacred gestures in Buddhist iconography and practice, the dharmachakra or ‘wheel of law’ mudra represents the Buddha’s first sermon at Sarnath. The teachings of this sermon are considered to have set the wheel of dhamma or dharma in motion, dispelling ignorance with the wisdom of reality. Both the hands are held at the chest level, with the right above the left and the thumbs of each hand touching the respective index fingers to form a circle. The tips of the left and right thumbs and index fingers in turn touch each other in such a way that the palm of the left hand faces inwards, while that of the right hand faces outwards. Among the five celestial Tathagata or Dhyani Buddhas, considered to represent cardinal qualities, the dharmachakra mudra is associated with Vairochana.  

Six-Armed Bodhisattva Avalokiteshvara sitting in a posture of royal ease: folio from a manuscript of the Ashtasahasrika Prajnaparamita; Pala, Undivided Bengal, India; Early 12th century; Opaque watercolour on palm leaf; 7 x 41.9 cm; The Metropolitian Museum of Art, New York
Prajnaparamita; Pala-Sena, Bangladesh; Early 12th century; Copper alloy; 8.8 x 5.5 x 4.5 cm; National Museum of Asian Art, The Smithsonian Institution, Washington, D.C.
Portable shrine with the Buddha Shakyamuni preaching his first sermon; Gandhara, Pakistan; c. 5th–6th century; Phyllitic green schist; 6.5 x 6.5 cm; The Metropolitian Museum of Art, New York
Buddha in dharmachakra mudra; Pala, Nalanda, Bihar, India; c. 9th–10th century CE; Bronze; 23.8 x 12.2 x 7.9 cm; Indian Museum, Kolkata, and Google Arts & Culture
Religious teacher; Possibly Karnataka, India; c. 1300–1400; Bronze; 16.8 x 10 cm; Rijksmuseum, Amsterdam
Seated Amitabha Buddha; Goryeo, Korea; Gilded bronze; National Museum of Korea, Seoul

According to some interpretations, the three extended fingers of the right hand are believed to represent the three vessels, or yanas, of the Mahayana Buddhism tradition, while those of the left hand are thought to denote the capacities for following these yanas. The symbolism is further extended to the open palms, of which the right suggests the method of conveying teachings and the left suggests their internalisation and the gaining of wisdom. When the left hand is shown holding a corner of the robe, as in early iconic representations, it symbolises renunciation. 

In some versions, the left hand is held at the hip level with fingers pointing downwards and palm outwards while forming the symbolic dharmachakra. A variant and possible derivative of the dharmachakra mudra is another ‘teaching’ gesture, the vitarka mudra, in which the left hand lies on the lap with the palm upturned, while the right hand forms the wheel shape with the palm turned outwards.