As a skilled and versatile teacher with mastery over pedagogic technique, the Buddha adopted different styles of presentation to communicate the Dhamma to his disciples. Often he would explain a teaching in detail (vittharena). Having introduced his topic with a short statement, technically called the uddesa or synopsis, he would then embark on the detailed exposition, the niddesa, also called the analysis, the vibhanga. In this stage of the discourse he would break the subject introduced by the synopsis down into its component strands, define each strand in turn, and draw out its implications, sometimes attaching a simile to illustrate the message of the discourse. Finally, he would restate the introductory declaration as a conclusion (niggamana), now supported by the entire weight of the foregoing analysis.
On other occasions, however, the Buddha would not teach in detail. Instead, he would present the Dhamma briefly (sankhittena), offering only a short, sometimes even cryptic, statement charged with a profound but highly concentrated meaning. The Buddha did not teach the Doctrine in this way in order to conceal an esoteric message or because he delighted in obscurantism. He used this technique because it sometimes proved a more effective means of shaking and transforming the minds of his auditors than would have been possible by a full elaboration. Although direct explanation of the meaning might have transmitted information more quickly, such a method might not have produced the lasting and edifying effect the Dhamma is intended to instil. But by requiring the disciples to reflect upon the meaning and to tease it out by sustained inquiry, as well as by mutual discussion, the Buddha ensured that when the disciples did come to understand his utterance, its message would penetrate deep into the silent recesses of the mind.
While such brief teachings would escape the understanding of the great majority of the monks, the mature disciples with sharp faculties of wisdom could readily fathom their meaning. Under such circumstances the ordinary monks, reluctant to trouble their Master with requests for explanation, would turn for clarification to the senior disciples whose comprehension of the Dhamma had already been confirmed by the Blessed One. So important did this function become in the early Buddhist Sangha that the Buddha himself established, in the ranks of his most eminent disciples, a separate category called "the foremost of those who analyze in detail the meaning of what was stated (by me) in brief" (aggam sankhittena bhasitassa vittharena attham vibhajantanam). The bhikkhu who was assigned to this position by the Master was the Venerable Maha Kaccana — Kaccana the Great, so called to distinguish him from others who bore the common brahmanical clan name of Kaccayana (shortened to Kaccana).
After his ordination as a bhikkhu, the Venerable Maha Kaccana usually resided in his homeland of Avanti, a remote region to the southwest of the Middle Country where the Buddha dwelt, and thus he did not spend as much time in the Blessed One's presence as some of the other great disciples did, such as Sariputta, Maha Moggallana, and Ananda. For this reason we do not find, in the records of the Sutta Pitaka, that the Venerable Maha Kaccana figured as prominently in Sangha affairs and in the Buddha's ministry as the aforementioned elders. Nevertheless, on account of the astuteness of his intellect, the profundity of his insight into the Dhamma, and his skill as a speaker, whenever Maha Kaccana did join the Buddha for extended periods, the other monks frequently turned to him for help in illuminating the meaning of brief statements of the Buddha that had been causing them bafflement. As a result, we find in the Pali canon a sheaf of discourses spoken by the Venerable Maha Kaccana that occupy a place of primary importance. These texts, always methodically refined and analytically precise, demonstrate with astounding lucidity the far-ranging implications and practical bearings of several brief statements of the Buddha that would otherwise, without his explication of them, escape our understanding.