律相感通傳 1.127

1.127

又云：「元制坐具之意，用表塔基之相。僧服袈裟在上，以喻法身之塔。塔基既不偏邪，坐具寧容長廣？縱使四周具貼，不違半搩之文，但以翻譯語略，但云各半搩手。十字而論，即是四周之義。」

He also said: "The original intention of instituting the sitting mat was to represent the form of a stūpa base. The saṅgha's wearing of the kaṣāya above symbolises the stūpa of the dharmakāya. Since the stūpa base is neither skewed nor crooked, how could the sitting mat be allowed to be overly long or wide? Even if strips are attached around all four sides, it does not violate the text of 'half a span'; it is merely because the translation was concise and only stated 'half a span each'. Discussing it crosswise, this is precisely the meaning of all four sides."