四分律比丘含注戒本 2.163

2.163

(Apart from detachable-legged beds, if one is on an individual sitting couch, or a single-board bed, or a secular bed, all are duṣkṛtas. Regarding non-offense: if one sits on a bed with turned legs, straight legs, curved legs, or no legs; if the bed supports are large; if the detachable-legged bed is fitted with tenons; if the upper floor is covered with boards, or carved with floral designs, or thickly covered; if one sits on a board bed; or if one sits on a bed with its legs detached—all are permitted.)