There are theories about the indefinite nature of the notation: a theory that '壹' is a writing error of '臺,' an alternative theory that they were written distinctly to avoid confusion, which can be guessed from '壹與遣,倭大夫率善中郎將掖邪狗等二十人送,政等還。因詣臺,' and another theory that the letter '臺,' which indicated the place in which the emperors of Wei lived, was not supposed to be used for the country name of the eastern barbarians.
表記のぶれをめぐっては、「壹」を「臺」の誤記とする説のほか、「壹與遣,倭大夫率善中郎將掖邪狗等二十人送,政等還。因詣臺,」から混同を避けるために書き分けたとする説、魏の皇帝の居所を指す「臺」の文字を東の蛮人の国名には用いなかったとする説などがある。