This study investigated the tone marks of the proper nouns of Korean origin in the Maedamanuscript(11th century) of Nihonsyoki by corresponding them with those of Middle Chinese sounds,Sino-Korean sounds of Middle Age, Go-on and Kan-on. The findings were as follows:First, our data were not in parallel with Middle Chinese sounds and showed a low agreement levelwith Sino-Korean sounds of Middle Age, which indicates that our data do not reflect the tone marks ofMiddle Chinese sounds and Sino-Korean sounds of Middle Age.
Second, the rising and departing tones of Go-on and Kan-on were added to our data as the low tone,which shows that our data have the "low tone phenomenon" characteristics and were under no one-sidedinfluence of either Go-on or Kan-on. The "low tone phenomenon" is the same as the result of theIwasaki manuscript. Those findings suggest that the tone marks of the proper nouns of Korean originpredict the feature of "low tone phenomenon" in the ancient manuscripts.
Finally, the Maeda manuscript was compared with the Iwasaki one, the oldest manuscript to whichthe rising tone was added. As a result, there was no common volume between them with a highpercentage of Chinese characters with the same tone marks despite different lines, which suggests thatthe tone marks of the proper nouns of Korean origin were passed down as a common system.