Working for any Japanese-owned company in Japan means loooooooong hours.
People work very hard (or give the impression of doing so) and that means working well past what normal people would consider a normal time for going home. They are very dedicated to their careers.
As a "freshman" in a company, you can also expect a shockingly low salary for the amount of work you put in. However, that is offset (usually) by commuter benefits and rent subsidy.