The Chinese government has detained Mr. Zhu Jianrong, an expert on Chinese politics and diplomacy and a professor at Toyo Gakuen University in Nagareyama, Chiba Prefecture. This is a sign that the Chinese leadership under President Xi Jinping is trying to strengthen its control of speech to increase its ideological grip on Chinese people.

Mr. Zhu is known for media comments on issues affecting Japan and China. His detention sent shock waves among Chinese researchers and journalists in Japan and among his acquaintances, both Chinese and Japanese. The Japanese government should urge the Chinese government to release Mr. Zhu and to adopt an open-minded policy toward Chinese people who express their opinions.

Mr. Zhu went to Shanghai, his native place, on July 17. Since then, his whereabouts have not been known. A press officer of the Chinese Foreign Ministry hinted at his detention Sept. 11, saying that Chinese nationals like Mr. Zhu must abide by China's state laws and regulations. Mr. Zhu married a Japanese researcher in 1984 and moved to Japan in 1986.