Does anyone know when manga-ka began writing about themselves in the sidebars or before and after the manga itself?

Thanks so much for your help--I need it for a class project :-)

I don't know about manga-ka but Jhonen Vasquez writes it during and in another more recent comic jellyfist it was done after but some american comics like Amazing Spider-man they have notes in the middle and in the back answer questions about themselves or the comic. If you want to know more about mangakas look for the book Manga: Masters of the art by Timothy Lehmann I found it in my library

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soji0083

I just always thought they WANTED that page's drawing to be smaller for their own reason but it didn't fit the standard page so they just filled it with SOMETHING.

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Click the Pokemon.

I'm pretty sure that the side bars are places where, in the original magazine, there were advertisements. (I know this is true for some series, but not sure if it's true for all of them.) The boxes that sometimes appear at the bottom of pages (I'm thinking of the early volumes of Fruits Basket in particular) are probably the same thing.

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"[English] not only borrows words from other languages; it has on occasion chased other languages down dark alley-ways, clubbed them unconscious and rifled their pockets for new vocabulary."
-James Nicoll, can.general, March 21, 1992

I don't know when (as in which year) they started having the author's talk in the manga tankobon either, but the bottom boxes at the beginning of chapters usually belonged to "What has happened so far..." (summary and character intro) in the magazine.

This is probably irrelevant...
In some shoujo magazines, each mangaka gets an entire page or a half page to interact with her fans. (This is where fans can submit their fanarts, vote for their favourite characters and wish their mangaka well.) This segment is usually removed when the manga chapter is published in a tankobon.