《仪礼·特牲馈食礼》
所祭者之子孙、兄弟亦玄冠玄端，立于主人的南边，面朝西，以北为上。
子姓兄弟如主人之服，立于主人之南，西面北上。
The descendants and brothers of the person being sacrificed to also wear black caps and black formal attire, stand to the south of the host, facing west, with north being the highest position.