How to Find the Formless and Markless from That Which Has Form and Marks

龙牙山里龙，形非世间色。世上画龙人，巧巧描不得。唯有识龙人，一见便心息。

Explanation: The dragon of Mount Longya refers to the five aggregates (pañca-skandha), and the dragon refers to the Ālayavijñāna. Within the five aggregates, the Ālayavijñāna dwells in seclusion, sustaining the body of the five aggregates and upholding the body of the five aggregates, so that the body of the five aggregates can function. Worldly forms are all material form (rūpa), with shape and appearance—visible, tangible, audible, smellable, and touchable. But this Ālayavijñāna is not like that: He is formless and without marks, invisible, untouchable, inaudible, and unsmellable. Even the most skilled dragon painter in the world cannot depict the image of the Ālayavijñāna, because the Ālayavijñāna has no worldly marks of the three realms; there is thus nothing to compare against and no place to begin. Only one who understands the Ālayavijñāna, recognizing Him with the eye of wisdom, will no longer chase outwardly after conditions. Because only this is the most real; everything else is illusory false appearances manifested and transformed by Him. Upon realizing this point, the mind comes to rest and no longer seeks outwardly.

Since the Ālayavijñāna is formless and without marks, how then can one find this dragon—the Ālayavijñāna—within the body of the five aggregates? One must understand the essential nature of the Ālayavijñāna, know how He appears, and where He appears, and then watch for Him at the places where He emerges and disappears. Within the body of the five aggregates, there are six openings: the eye, ear, nose, tongue, body, and mind. Although this dragon never leaves the cave with a body, He will often roar from within these six openings. When He roars, as long as one can recognize His voice, one can find His traces. From then on, one can follow the sound to recognize self-nature (svabhāva) and find the way home.