Japan and China recently marked the 50th anniversary of the normalization of diplomatic relations, but traces of around 7.46 million poison gas weapons produced mainly during their war from 1937 to 1945 remain in both countries.

Some of the weapons abandoned or disposed of at the end of the Sino-Japanese War are still taking a toll on lives and livelihoods.

"I got sick because of the water. I want to die," Ryuji Aotsuka, 21, a resident of Kamisu located about 100 kilometers east of Tokyo, screamed while holding a knife at his home in September 2021.