Premise: The Imperial Japanese Navy Air Service (大日本帝國海軍航空隊 , Dai-Nippon Teikoku Kaigun Kōkū-tai ) was the air arm of the Imperial Japanese Navy during World War II. The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War.
Hypothesis:  during World War II, the Imperial Japanese Navy Air Service was the air arm of the Imperial Japanese Navy