大毘盧遮那成佛經疏 17.28

17.28

In the fifth month, going from the gold circle to water, equal to all buddhas, one dwells within the vajra-water circle. That is, form a square yellow maṇḍala containing a round white maṇḍala, with one's body seated within. Below the navel is yellow, and from the middle up is white. Inside, form no mudrā, but use the two syllables A and VA; the rest is as above. During these five months, one must not eat; all food is abstained from. That is, cutting off all food, one takes only the two mantras as the in-and-out breath for nourishment. From the fifth month onward, practicing the conduct of non-attachment and freedom from self, identical to the quiescent single characteristic, one is equal to the buddhas.