《明史·志·卷三十六》
凡是虞祭，安葬这天，中午举行祭祀，逢天干的乙、丁、巳、辛、癸偶日举行第二次虞祭，逢甲、丙、戊、庚、壬奇日举行第三次虞祭。
凡虞祭，葬之日，日中而虞，柔日再虞，刚日三虞。
For every Yu sacrifice, on the day of the funeral, a sacrifice takes place in the afternoon, and the second Yu sacrifice takes place on the alternating days of the heavenly stems of Yi, Ding, Si, Xin, and Gui, and the third Yu sacrifice takes place on the odd days of Jia, Bing, Wu, Geng, and Ren.