In which theatre of conflict was 'Operation Sei-go' carried out by the Japanese armed forces during WW II?

During World War II, Japan infamously deployed biological weapons in attacks that infected and killed thousands of Chinese citizens.

Following the Doolittle raid over Tokyo in 1942 (a daring air raid by the U.S. forces on the main island of Honshu), Japanese troops launched a revenge campaign called 'Operation Sei-Go', which included the employment of cholera, typhoid, plague and dysentery bioweapons—which in addition to killing tens of thousands of Chinese, may have backfired and killed 1,700 Japanese troops by one estimate.

'Operation Sei-go', also known as the 'Zhejiang-Jiangxi campaign', was a campaign by the China Expeditionary Army of the Imperial Japanese Army under Shunroku Hata and Chinese 3rd War Area forces under Gu Zhutong in the Chinese provinces of Zhejiang and Jiangxi from mid May to early September 1942.

The Japanese troops used biological weapons against Chinese soldiers and civilians alike. Japanese soldiers also committed massacres throughout the battle, resulting in over 300,000 Chinese deaths. Japanese commander Shunroku Hata later served six years in prison for his "failure to prevent atrocities".