Jim Harbaugh stood on the Stanford sideline at the University of California’s Memorial Stadium in 1980 and heard the public address announcer welcome fans to “The Big Game.” That clashed with Harbaugh’s beliefs about college football rivalries.

Then a junior in high school, Harbaugh had spent the previous seven years in Ann Arbor, Mich., getting his first taste of a rivalry that he would come to know intimately — as Michigan’s quarterback and later as his alma mater’s coach.

So in that moment at Cal 39 years ago, Harbaugh nudged his father, Jack, who was in his first season as Stanford’s defensive coordinator, to quietly set the record straight.

“I think we both know where the real big game is being played today,” Jack Harbaugh recalled his son saying.