Earlier quoted context omitted.
You seem to completely ignoring Japan's wars of invasion against China, Korea, Indochina, and basically every border other than "America" first. Or for that matter, the rest of World War II which had been going on for over a year.
2 years, really. It kicked off in late 1939 with the German invasion of Poland, subsequent declarations of war by Britain and France, and then an awkward months-long period of shuffling about known as the "Phony War".
Japan's intrusions and occupations of Korea and China lasted decades before 'it kicked off in late 1939'.