One-pointed concentration, fixing one’ s full attention on one place, object, or idea at a time. It is the sixth limb, or requirement, to attain full Self-realization as outlined in the Yoga Sutras attributed to the sage Patanjali.
Dharana is the ability to bring the mind into focus and to hold the concentration on a single point. In true dharana all body-consciousness and restless thoughts cease, enabling one to focus on the object of meditation without distraction.
In the Hindu epic, The Mahabharata, Arjuna demonstrates dharana. Dronacharya, the teacher of archery, is holding a contest. There is a statue of a vulture placed high in a tree, and its head is the target. As each student approaches to take his turn Dronacharya asks him what he sees. One replies, “I see you, my teacher, the tree, the sky, and all who have gathered around.” This student misses his shot. The next replies in a similar manner, and he, too, misses.
Finally, after everyone else has failed to hit the target, Arjuna approaches. In response to the question he answers, “I see the head
of the bird.”
Dronacharya asks, “Don”t you see anything else?”
Arjuna replies, “I see only the head of the bird.”
He then shoots his arrow and hits it right on target. [ref]How to Meditate, by Jyotish Novak. Chapter 13, “Patanjali’s Eightfold Path.”[/ref]