I know Mobile Suit Gundam (episode 1) did it in 1979, that's the earliest I know of.
How about that!
Do you know where the toast-mouth-school-late-run thing cliche originated? What did it appear in before, say, 1986's Project A-ko? Please educate the masses! Our children need to know this.
I’m afraid I don’t know!
HELP US, FOLLOWERS! WE MUST UNRAVEL THIS MYSTERY!!