A stone artifact dating to around 2,000 years ago that appears to have writing on it is causing a stir in the world of academia as the find could constitute the oldest example of written language in Japan.

The key to the mystery lies in whether there really are written characters, and if so, whether they were written in Japan.

Researchers insist the fragment found in the Tawayama archaeological site in Matsue, Shimane Prefecture, bears faint kanji characters scribbled in India ink.

But skeptics said the presence of writing in India ink could not be confirmed through infrared imaging, and called for further research.

The artifact is 9 centimeters long and originates from the latter part of the Yayoi Pottery Culture Period (1000 B.C.-A.D. 250)

Takeo Kusumi, a researcher with the Fukuoka city government’s Archaeological Property Section, said the artifact could be part of an inkstone. He maintained that kanji characters were discernible on the rough surface.

He presented his opinion at a conference of archaeologists held in Ogaki, Gifu Prefecture, on Feb. 1. 

Kusumi is in no doubt the remnant is part of an inkstone created in Japan, citing marks left by the use of the inkstick.

He suggested that two, dark lines seen near the center on the reverse side could be two Chinese characters--one representing the first of 12 signs of the Chinese zodiac and the other representing the fifth of the 10 calendar signs--written in clerical script, a style in the Chinese writing system.

In Japan, the oldest known letters confirmed to date were jotted down on clay vessels excavated in Fukuoka and Mie prefectures, dating to the second and third century.

The characters in the latest discovery are thought to have been written around the beginning of the first century, hence the buzz about the artifact found at the Tawayama remains.

The period in China falls between the latter part of the Earlier Han period and the early years of the Later Han period.

Yasuo Yanagida, a visiting professor of archaeology with Kokugakuin University, agrees with Kusumi that Chinese characters are present.

Yanagida, who has done much research on inkstones originating in the Yayoi Pottery Culture Period, suggested the letters could represent other Chinese characters, including the seventh of the 12 signs of the Chinese zodiac, the ninth of the 10 calendar signs, and the 11th sign of the Chinese zodiac.

Yanagida and his colleagues noted that 200 or so inkstones from the Yayoi Pottery Culture Period and the following Kofun Period, which lasted from the late third century to the seventh century, have been unearthed around the nation. Most of them were discovered in western Japan.

If the stone fragment found at the Tawayama site is confirmed to be an inkstone, researchers said it could provide important clues as to when people living on the Japanese archipelago began using a written language and how writing spread.

But Junichi Takesue, a professor of archaeology at Fukuoka University, was skeptical that the dark lines may symbolize letters.

He referred to a study using infrared ray imaging by the Matsue municipal government’s buried cultural properties section that did not confirm the existence of characters written in India ink.

“There is the possibility that what were left on the stone remnant are letters, but we cannot reach a definitive conclusion at this stage yet,” he said.