A group of Japanese researchers have issued an emergency appeal for a prominent Chinese scholar at Hokkaido University of Education, who they say has been uncontactable since he left for China to attend a family funeral in June.

Friends and colleagues have not been able to get in touch with Yuan Keqin, a professor of East Asian political history, for over six months, according to the appeal released Tuesday by Hokkaido University professor Akihiro Iwashita and other researchers.

Yuan, who was born in China's Jilin Province in 1955 and studied law at Hitotsubashi University graduate school in Tokyo, is a permanent resident of Japan.

He has not been heard from since July after friends and colleagues learned he was being treated for high blood pressure, Iwashita said.

Hokkaido University of Education said it hopes to get in touch with Yuan soon to confirm how he is doing.

Chinese authorities in September detained Hokkaido University professor Nobu Iwatani for alleged spying, subsequently releasing him in November. Iwatani specialized in studies on the Chinese Nationalist Party during the Sino-Japanese War from 1937, a field close to Yuan's area of expertise.

"We cannot deny the possibility that professor Yuan may be detained as well. If anyone has any information about his safety, please contact me," said Iwashita.

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