四分律刪繁補闕行事鈔 2.133

2.133

Eleventh is the araṇya boundary. The Vinaya states: An araṇya has no boundary (meaning it is isolated in the open wilderness with no distinct boundaries, so its extent is provisionally measured by trees). The space between eight trees, with seven bows between each tree, a bow being four cubits long; the total calculation is fifty-eight paces, four feet, and eight inches; including its peripheral extension, it exceeds seventy [paces]. Next it explains that if it is insufficient, one takes from external parts to complete its use.