Japan and weapons of mass destruction

The Empire of Japan extensively used and researched chemical and biological weapons (CBW) during the Second Sino-Japanese War as part of Japanese war crimes. Japan is the only country ever attacked with nuclear weapons, by the United States' 1945 atomic bombings of Hiroshima and Nagasaki at the end of World War II. During the Cold War, the United States stationed chemical and nuclear weapons in Japan from the early 1950s to early 1970s.

Source: Wikipedia — Japan and weapons of mass destruction (CC BY-SA 4.0)