《晋书·志·第九章》
日食将要发生时，天子穿素色衣服离开正殿，宫内宫外严密警戒。
日将蚀，天子素服避正殿，内外严警。
When an eclipse was about to occur, the Emperor would leave the main palace wearing plain clothes, and the palace would go on high alert both inside and outside.