The essence of the Prajñāpāramitā Sūtra taught by Buddha Śākyamuni in the second turning of Dharma Wheel was condensed into the Prajñāpāramitāhṛdaya (Heart of the Perfection of Wisdom Sūtra; C. Xin Jing). Even though the Heart Sūtra translated by Xuanzang contains only 260 words, it is able to encapsulate the full meaning of 600 volumes of Prajñāpāramitā Sūtra. Based on studying sūtras and sastras, this paper reveals that the main character of the Heart Sūtra, Bodhisattva Avalokitêśvara (C. Guanzizai) was practicing the profound prajñāpāramitā, directly perceived the mind of emptiness-nature which is inherently without birth and death, and brought forth prajñā, the wisdom regarding the ultimate reality; thus the five aggregates of the body-mind which can see and hear, apprehend that the five aggregates are illusory, arising and ceasing dharmas of birth and death. The truth that the five aggregates are ephemeral and filled with suffering and emptiness can then be thoroughly understood, thereby liberation from the suffering of cyclic existence in the three realms can be attained. The Heart Sūtra states that there are two types of mind known as the observer and the observed, through being able to directly witness the false and deceitful observing mind and the inherently tranquil and unhindered observed mind, the other shore can be reached to attain liberation from the suffering of cyclic existence.