A Chinese court on Wednesday sentenced a Japanese man to three and a half years in prison on espionage charges, the Japanese embassy in Beijing confirmed.

The man, who has been in detention since March 2023, was not identified by the embassy. Japan’s Kyodo News reported he is in his 60s and works for Astellas Pharma Inc., a major Japanese pharmaceutical company.

He was formally charged with espionage last August, with his first court hearing held in November. Chinese authorities have not disclosed details of the allegations.

The Beijing No. 2 Intermediate People’s Court, which handed down the sentence, did not issue a public statement after the ruling. Japanese Ambassador to China Kenji Kanasugi, who attended the court session, called the verdict “extremely regrettable.”

Speaking afterward, he said Japan continues to demand the early release of all detained Japanese nationals and warned that such cases remain “one of the biggest obstacles to improving people-to-people exchanges and public sentiment between Japan and China.”

Japanese reporters were barred from observing the proceedings. In a statement, the embassy urged Chinese authorities to ensure humane treatment of detainees and greater transparency in judicial processes.

Chinese Foreign Ministry spokesperson Lin Jian defended the handling of the case, saying authorities acted “in strict accordance with the law” and stressing that foreign nationals in China who obey the law “have nothing to worry about.”

Since China introduced an anti-espionage law in 2014, at least 17 Japanese citizens with business or personal ties to China have been detained, Kyodo reported. Five remain in Chinese custody. In 2022, a Japanese diplomat was briefly detained for questioning, drawing sharp protests from Tokyo.

Japan has grown increasingly wary of China’s expanding influence and views the risk of detention on spying allegations as a rising concern, particularly among its business community. The Japanese embassy in Beijing has even published a safety handbook urging visitors to exercise extra caution.

While the Japanese government continues diplomatic efforts to secure the release of its citizens, Wednesday’s ruling highlights the ongoing tension between Asia’s two largest economies over security, transparency, and trust.