釋氏要覽 3.43

3.43

曲禮云。非飲食之客席。間函丈（注函容也。謂講問冝相對容丈足以指劃也）。

The Quli says: ‘For the mat of a guest when not dining, leave a ten-foot space (hanzhang).’ (The commentary says: ‘Han means to accommodate. It means that when lecturing and asking questions, one should face each other with a space accommodating ten feet, sufficient for pointing and gesturing.’)