The Essentials of Buddhist Philosophy, p141The Threefold Body (Trikaya) of the Buddha is mentioned as Buddhahood; its representative theory is held by the Tendai School.
Every Buddha of Perfect Enlightenment is supposed to possess three bodies. Although the original names of Dharma-kaya, Sambhoga-kaya, and Nirmana-kaya mean literally ‘Principle-body,’ ‘Enjoyment-body,’ and ‘Transformation-body,’ the term ‘body’ in the ordinary sense is rather misleading because it conveys the idea of a bodily existence.
The Principle-body or Truth-body is the Ideal or the Principle or Truth itself without any personal existence. It is identical with the Middle Path Truth.
The Enjoyment- or Reward-body is the person embodied with real insight, i.e., the body attained as the value of a long causal action. It is twofold: (a) The body for self-enjoyment, i.e., the person when he is enjoying his own enlightenment. (b) The body manifested for the enjoyment of others, i.e., bodhisattvas above the primary stage of saintly perfection.
The Transformation-body is a body variously appearing to save people. It is also twofold: (a) The body exclusively for bodhisattvas of the primary stage that is a superior body of Transformation. (b) The body for those who are prior to the primary stage.
Every Buddha has these three aspects. While a Buddha represents the Principle or Truth which he himself has realized, he is, on the one hand, the realizer of the ideal or the enjoyer of his Enlightenment and, on the other hand, is the giver of the ideal or the deliverer of all who are suffering or perplexed. Thus the Buddha is viewed as the ideal (Enlightenment) itself, the enjoyer of it (the Enlightened), the giver of it to others (the Enlightener). The Enjoyment-body is obtained by the Buddha as a reward for long effort, while the Transformation-body is freely assumed by him in order to meet the needs of others and the world.
The Three Bodies of the Buddha are further divided into four, five, six or ten, but the above stated Threefold Body of the Tendai School may be regarded as the fundamental theory of Buddhahood.
