大毘盧遮那經阿闍梨真實智品中阿闍梨住阿字觀門 1.15

1.15

故總而言之，相入自然又解分為三分：頭為初分（黃色）；咽、心為中分（白色）；臍為後分（黑色）。若用迦字為輪，即不用劍字；若用劍字為輪，即不用迦字，斯謂發菩提心，行果為中，大寂為後，是名三分。阿闍梨既如是三重成身已，其曼荼羅并及弟子亦如是布之，三事皆成，是名祕密曼荼羅。若不了達此中意趣，難依前事法而作，不名善作，虛費其功夫，亦無所成也。

Therefore, speaking generally, the spontaneous mutual entry is also explained as divided into three parts: the head is the first part (yellow); the throat and heart are the middle part (white); and the navel is the final part (black). If one uses the syllable *ka* as the wheel, one does not use the syllable *kha*; if one uses the syllable *kha* as the wheel, one does not use the syllable *ka*. This is called the arising of the bodhicitta, with practice and fruit as the middle, and great stillness as the end; these are named the three parts. After the *ācārya* has thus formed the body through the three tiers, they also distribute them in this way onto the maṇḍala and the disciple; when the three matters are all completed, this is named the secret maṇḍala. If one does not thoroughly comprehend the intended meaning here, it is difficult to proceed based on the external ritual; it cannot be called well performed, the effort is spent in vain, and nothing will be accomplished.