This study investigates 260 examples of words that have the combination ""AB-BA"" in modern Japanese, whereas in modern Chinese there is only ""AB"" but not ""BA"" and their origins. According to the results of the survey, there are 158 words from Chinese literature and 86 words from Japanese literature, 6 words from both Chinese and Japanese literature, and 10 words with no examples or origins indicated. Among the words from Japanese literature, we find that there are more words from modern Japanese literature, specifically from the Meiji period onwards. The author believes that one of the reasons for the failure to include BA in ancient Chinese dictionaries is because these words are derived from recent Japanese literature. differences in words and mis-translations.