It is written in the Vinaya Pitaka that the Baddhasima (the area in which the monks perform the Sanghakamma or Buddhist sacred ceremonies) must be able to accommodate 21 seated monks, with a space the length of a forearm between each monk. The area should also not be larger than three yojana which is about . This is probably meant to mean the maximum circumference. In other words, the Baddhasima should not be too small, nor too big.
