Ever heard of Josh White ?

He played before they had the little skinny strings we have now (developed about the time the Beatles started). Players bend the string to move the note higher.

Many years ago, he was on the Dateline Boston TV show with Chebeaguer Ted Wood. He broke a string (next to impossible). Live TV so - he replaced the string, while singing and occasionally turning to hit a note on a nearby piano.

Josh on Wikipedia