殷墟卜辭的「亦」，一般都解釋為「也」或「又」，這對某些卜辭是恰當的。但對某些卜辭卻未必如此。本文從卜辭和文獻論證，認為某些卜辭的「亦」字應該讀為「夜」，是同音假借的用法。進而探討殷商時代夜間作戰的可能性，以及夜間可能的祭祀或農業活動。

The character ”亦” in oracle bone inscriptions from the Yin Ruins is usually explained as meaning ”也 (also, still)” or ”又 (again, also, but)”. When discussing some oracle bone inscriptions, these explanations are suitable. However, this is not always the case. This article uses oracle bone inscriptions and documentary evidence as a basis for discussion and argues that the ”亦” seen in some oracle bone inscriptions should be read as ”夜 (night)”. This is an example of ”亦” being used as a homophonic and phonetic loan. The article also explores the possibility that, during the Yin-Shang dynasty, battles, sacrifices, and agricultural activities may have sometimes taken place at night.