《明史·志·卷二十七》
皇帝亲自作文祭告皇祖，定于丙年、辛年举行一次，敕令礼部准备礼仪择日举行。
帝自为文告皇祖，定丙、辛岁一行，敕礼部具仪择日。
The emperor composed a text himself to inform the imperial ancestor that it would be held once every six years, and ordered the Ministry of Rituals to select an appropriate date.