四分律刪繁補闕行事鈔 1.289

1.289

其大界內相，東北二面，以小牆外院為相。南西二面，以大院牆內為相。若明外相，必在院外唱之。若在牆內唱者，至西南角戒場外自然界邊，則與內相俱合，則不分彼此之異。又不得入大院牆唱之，由不見其相故。

As for the inner marks of the great boundary, the northeast two faces use the outer compound of the small wall as their marks. The south and west two faces use the inner side of the wall of the great compound as their marks. If proclaiming the outer marks, one must proclaim them outside the compound. If one proclaims them inside the wall, then upon reaching the southwest corner at the edge of the natural boundary outside the ordination platform, they will coincide with the inner marks, and the distinction between this and that will not be differentiated. Furthermore, one must not enter within the wall of the great compound to proclaim them, because their landmarks cannot be seen.