四分律刪繁補闕行事鈔 1.261

1.261

三明小界者。此並因難事，恐廢法事，佛隨前緣，故開結之。並無正量，隨人坐處，即為界相。一為受戒開結小界，舊準戒場，身外有界；今依文取義，全無外相，如正加中。二為說戒事，下至四人直坐。三為自恣事，下至五人圓坐。此三無外量者，由是難開，隨人多少；若限約外量，終非遮難。故文云：今有爾許比丘集者，止取現集之僧；坐處有地，依地結之。若事作已，即制令解；不同前二，以久固作法，人所依止。

Third, explaining the small sīmā (khaṇḍasīmā): these are all demarcated on account of adverse circumstances, out of fear that Dharma-proceedings would be abandoned, the Buddha having permitted their demarcation according to the preceding circumstances. None of them have a fixed standard measurement; the places where people sit simply serve as the marks of the sīmā. The first is demarcating a small sīmā opened for upasampadā: formerly based on the precept platform, there was a sīmā outside their bodies; now, deriving the meaning based on the text, there are no external marks at all, as in the rite of formal empowerment. The second is for the matter of upoṣadha recitation, down to four people sitting in a straight line. The third is for the matter of pravāraṇā, down to five people sitting in a circle. The reason these three have no external measurements is that they are permitted due to emergencies according to the number of people; if one were to restrict them with external measurements, it would ultimately not avert the obstruction. Therefore the text says: 'There are now assembled so many bhikṣus'—it merely takes the currently assembled saṃgha; where they sit there is ground, and one demarcates it based on that ground. Once the matter is done, it is immediately prescribed to disband it; it is not like the previous two, which are long-lasting rites upon which people rely.