大毘盧遮那成佛經疏 17.4

17.4

As for the first mudrā, make a hollow-palmed saṃpuṭa añjali; the two wind and earth fingers are straightened and separated, while the rest remain as before—this is it. This is the mudrā of the arising of the Tathāgata Vairocana's great majestic virtue. From within this arises the Tathāgata's great majestic virtue; this is the illumination of the sarvajñajñāna. Its maṇḍala is made triangular, and around its four sides there are further four triangles surrounding it; hence it is said to 'surround' it. Within it, one should visualize the Bhagavān Vairocana abiding in its center. As for the triangular maṇḍala, one should visualize an eight-petaled flower, and upon the lotus receptacle produce the triangular maṇḍala. This is the previous yoga seat: make this triangle with its apex pointing downward, and its color is red. Previously it was said that the triangle's apex points upward; here it points downward because the functional meaning is different. Imagine the Buddha within this, forming the mudrā of majestic radiance. Its mantra is: