Kaiju (Japanese: 怪獣, Hepburn: kaijū, lit. "strange beast") is a Japanese genre of films featuring giant monsters. The term kaiju (which comes from the Chinese text Classic of Mountains and Seas) can refer to the giant monsters themselves, which are usually depicted attacking major cities and engaging the military, or other kaiju, in battle. The kaiju genre is a subgenre of tokusatsu (特撮, "special filming") entertainment.
The 1954 film Godzilla is commonly regarded as the first kaiju film. Kaiju characters are often somewhat metaphorical in nature; Godzilla, for example, serves as a metaphor for nuclear weapons, reflecting the fears of post-war Japan following the atomic bombings of Hiroshima and Nagasaki and the Lucky Dragon 5 incident. Other notable examples of kaiju characters include Rodan, Mothra, King Ghidorah,and Gamera.