This paper contributes to considerations on the four-dhyanas of the Sarvastivada . Data center on the Abhidharmakosa , Abhidharma-mahavibhasa , and Abhidharma-nyayausara . In the Sarvastivada , the four- dhyanas are applied to the rupa-dhatu . In this combination, dhyana is divided into two sorts, upapattidhyana and samapattidhyana , cause and effect. Originally these two seem to have been separate. Now, the essence of dhyana is samadhi , and samadhi is cittaikagrata . Apparently using several terms help clarify the idea. In order to understand dhyana from a different viewpoint 18 subdivisions are introduced in the 4 dhyanas . These, it is said, may be subsumed under eleven. Two levels each are introduced into each dhyana . Overall, it is a very complicated system. But the meaning of dhyana is abundantly clear.