Large Tibetan thangka painting of Mahakala Shadbhuja
A wrathful manifestation of Avalokiteshvara, bodhisattva of compassion and principal protector of the Gelugpa and Shengpa Kagyu lineages of Tibetan Buddhism, Mahakala Shadbhuja is the ‘Swift-Acting Lord of Pristine Awareness with Six Hands’ in Tibetan mGon-po phyag drug-pa, མགོན་པོ།.
On the back of the thangka is the dedicatory mantra oṃ āḥ hūṃ and there is a good explanation of it HERE. In short, oṃ (or aum) represents the body and essence of form, āḥ speech and the essence of sound, and hūṃ represents thoughts and emotions and the essence of mind. The repeated recitation of the mantra is a meditation practice for purifying these physical, energetic and psychological realms.
The thangka was painted in the 20th century and is 124cm x 88cm including a 5cm black border.