This article delves into the development of Japanese Chinese character variations, and how they fit into the broader study of Chinese characters. By examining the differences between early Japanese kanji and modern Japanese writing systems, as well as the varying approaches of Chinese and Japanese scholars in studying Japanese kanji, we can propose a more fitting classification and naming method better suited to studying Chinese characters. To that end, we take the Wamyō Ruiju Shō (倭名類聚抄) as an example, exhaustively sorting out the situation of variant characters in the manuscript across different eras, and referring to other ancient Chinese dictionaries from the same period. This article introduces concepts like “inherited variants” and “Japan saved variants” to make studying these characters more comprehensive.