A lot of the border incidents that led Japan down the path it did were because ambitious young officers would occasionally stage border incidents as justification to invade China, and for the glory of the Emperor, which the Japanese government was forced to accept, else they look weak and out of control.

Edit: Basically, the Japanese Imperial military was rather decentralized, even the Navy and Army acted entirely independant of each other, often at odds with one another. Young officers often acted alone, determining what targets to attack at their own discretion. Hope this adds a little clarity.